Functionalized lead acid battery separators, improved lead acid batteries, and related methods

ABSTRACT

In accordance with at least selected embodiments, the present application or invention is directed to novel or improved porous membranes or substrates, separator membranes, separators, composites, electrochemical devices, batteries, methods of making such membranes or substrates, separators, and/or batteries, and/or methods of using such membranes or substrates, separators and/or batteries. In accordance with at least certain embodiments, the present application is directed to novel or improved porous membranes having a coating layer, battery separator membranes having a coating layer, separators, energy storage devices, batteries, including lead acid batteries including such separators, methods of making such membranes, separators, and/or batteries, and/or methods of using such membranes, separators and/or batteries. The disclosed separators and/or batteries have improved charge acceptance, improved surface conductivity, improved oxidation resistance, reduced acid stratification, improved resistance to metal contamination induced oxidation, reduced black residue, improved wettability, and/or improved stiffness.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to and benefit of U.S. ProvisionalPatent Application Ser. No. 62/237,174, filed on Oct. 5, 2015. Theentire contents of which are herein incorporated by reference.

FIELD

In accordance with at least selected embodiments, the presentapplication or invention is directed to novel, improved or optimizedporous films, membranes or substrates, functionalized, coated or treatedporous films, membranes or substrates, novel, improved, optimized,functionalized, coated, or treated separator membranes, separators,multilayer separators, lead acid battery separators, or composites,electrochemical devices, batteries, or cells including such films,membranes, substrates, separator membranes, separators, lead acidbattery separators, or composites, novel, improved or optimizedcombinations or systems of plates or electrodes with such films,membranes, substrates, separator membranes, separators, lead acidbattery separators, or composites, methods of making such films,membranes, substrates, separator membranes, separators, lead acidbattery separators, composites, systems, combinations, cells, devices,and/or batteries, and/or methods of using such films, membranes,substrates, separator membranes, separators, lead acid batteryseparators, composites, systems, combinations, cells, devices, and/orbatteries. In accordance with at least certain embodiments, the presentapplication is directed to novel, improved, or optimized,functionalized, coated, or treated microporous membranes, batteryseparator membranes, lead acid battery separator membranes, separators,and/or lead acid battery separators having at least one functionalized,coated, or treated surface on at least one side thereof, having at leastone coating, film, layer, or material on at least one side, rib orsurface thereof, energy storage devices, cells, systems, combinations,and/or batteries including such membranes, battery separator membranes,lead acid battery separator membranes, separators, and/or lead acidbattery separators, methods of making such membranes, battery separatormembranes, lead acid battery separator membranes, separators, and/orlead acid battery separators, and/or methods of using such membranes,battery separator membranes, lead acid battery separator membranes,separators, lead acid battery separators, composites, combinations,systems, devices, cells, and/or batteries, and/or the like.

BACKGROUND

Lead acid batteries have four basic components, a positive electrode,which may be a lead or lead alloy grid pasted with a lead oxide positiveactive material (PAM) coating, a negative electrode, which may be a leador lead alloy grid pasted with a negative active material (NAM) coating,a separator, and a liquid electrolyte, generally sulfuric acid. Toprevent physical contact between the electrodes of opposite polaritywhile allowing for ionic flow, electrically insulating porous separatorsare placed between the electrodes. Separators often include amicroporous polymer membrane or material, for instance a polyolefinmembrane, such as polyethylene (PE) membrane. In a lead acid battery,the area in which the electrolyte and positive electrode meet is calledthe interfacial “oxidation zone.” The oxidation may be purely chemicalor purely electrochemical or a combination of both. This oxidation zoneis on the order of several hundred microns or μm and extends into theelectrolyte where the separator is placed. Polyethylene and similarpolymers are not inherently oxidation resistant during the batteryoperation, and as such may undergo accelerated oxidation, especiallyportions of the separator which are located in the oxidation zone.Oxidation of the separator material may lead to reduced batteryperformance and life span.

A typical separator will often surround either, or both, of the positiveor negative electrodes, usually in an envelope, pocket or sleeveconfiguration. The envelope or sleeve is obtained from a single sheet ofseparator material which is folded into the shape necessary to surroundthe electrode. This folding and cutting is often done with automatedequipment in a continuous fashion. Over time, automotive batterymanufacturers have reduced the backweb thickness of separators from 250μm to 150 μm, because reducing the volume of the separator allowsadditional electrolyte and electrode material to be present in thebattery, increasing power and performance. However, because bendingstiffness is related to the cube of the thickness, even small reductionsin thickness can substantially reduce bending stiffness. For instance, a30% reduction in thickness can result in a 70% decrease in bendingstiffness. The reduced separator stiffness presents manufacturingchallenges with existing equipment. For instance, reduced stiffnessincreases the propensity for inadvertent folds and creases, leading tohigher rejection rates of the finished separator. Reducing manufacturingspeed can reduce rejection rate, however, the productivity loss thataccompanies such reduction is often commercially undesirable orinfeasible.

When lead acid batteries are deeply discharged the gravity of theelectrolyte will decrease as the sulfuric acid is a participant in theenergy storage reactions. Upon recharging, pure sulfuric acid, which hashigher density than bulk electrolyte, is created at the surface of theelectrodes (i.e., a boundary layer). At the boundary layer only theouter portion of sulfuric acid will diffuse into the bulk electrolyte,while the remaining sulfuric acid, because it is heavier than theelectrolyte, will collect in the bottom of the battery. This separationof sulfuric acid from bulk electrolyte is termed “acid stratification.”The reduced level of acid at the top of the battery inhibits plateactivation and increases corrosion. Also, increased acid concentrationat the bottom artificially raises the voltage of the battery, which caninterfere with battery management systems. Overall, acid stratificationcauses higher resistance which leads to shorter battery life.

Hence, there is a need for improved separators and/or batteries. Forexample, there may be a need for improved separators or batteries thatmay provide improved or enhanced charge acceptance, surfaceconductivity, oxidation resistance, wettability, bending stiffness,and/or cycle life, and/or reduced acid stratification, a need forbatteries, especially lead acid batteries, with improved chargeacceptance and/or reduced acid stratification, a need for batteryseparators with improved wettability, improved surface conductivity,improved oxidation resistance, and/or increased stiffness, and/or a needfor manufacturing processes which allow the rapid production of batterycomponents, including separators, with reduced rejection rates offinished separators.

SUMMARY

In accordance with at least selected embodiments, aspects or objects ofthe present application or invention, novel or improved separators,batteries and/or methods may address the above needs, may address theneed for improved separators that may provide improved or enhancedcharge acceptance, surface conductivity, oxidation resistance,wettability, bending stiffness, and/or cycle life, and/or reduced acidstratification, for improved batteries, especially lead acid batteries,with improved charge acceptance and/or reduced acid stratification, forimproved battery separators with improved wettability, improved surfaceconductivity, improved oxidation resistance, and/or increased stiffness,and/or for improved manufacturing processes which allow the rapidproduction of battery components, including separators, with reducedrejection rates of finished separators, and/or may provide novel orimproved separators, batteries and/or methods, and/or may provideimproved or enhanced charge acceptance, surface conductivity, oxidationresistance, and/or cycle life, reduced acid stratification, improvedresistance to abuse or contamination, improved resistance to metalcontamination induced oxidation, reduced black residue, improvedwettability, improved stiffness, improved usable life of the separator,or combinations thereof.

In accordance with at least one embodiment, aspect or object of thepresent application or invention, oxidation of the separator isprevented to enhance, improve or retain the desired cycle life of thebattery, the usable life of the separator, or both.

In accordance with at least one embodiment, aspect or object of thepresent application or invention, a layer of stiffer material on the topof substrates may replace increasing the stiffness of the bulk of theseparator, and thereby avoid a possible rigid, brittle bulk of theseparator.

In accordance with at least particular embodiments, the batteryseparators described herein are directed to a multilayer or compositemicroporous membrane battery separator which may have excellentoxidation resistance and are stable in a lead acid battery system. Inaccordance with at least other selected embodiments, the presentinvention is directed to a battery separator having a layer whichincreases oxidation resistance, improved oxidation resistance in thepresence of metal ion contamination such as chromium ions, reduces acidstratification, improves surface conductivity, improves chargeacceptance, increases stiffness and processability, and/or increasessurface wettability.

In accordance with at least certain selected embodiments, the presentinvention is directed to a separator for a battery that is a microporouspolymer membrane functionalized, coated, treated, or the like to add atleast one material, treatment, function, or layer on at least one sidethereof. In certain selected particular embodiments, the material,treatment, function, or layer may or may not include a binder, mayinclude one or more materials such as silica, silicon oxides, alumina,aluminum oxides, metals, metal oxides, conductive carbon materials, acidstabilized cellulose, and/or the like, and/or may include one or moreconductive or dielectric or insulating layers.

In accordance with at least certain embodiments, a method of obtainingimproved separators is provided in which a treatment, material or layeris applied to at least one surface or side of a polymeric microporousmembrane, a polyethylene (PE) microporous membrane, a woven or nonwovenmaterial, a nonwoven glass mat, a nonwoven absorptive glass mat (AGM), anonwoven or woven PET, cellulose nonwoven mat, and/or the like. Thematerial, treatment or layer can be applied by vapor deposition,chemical deposition, vacuum assisted methods, PVD, CVD, TD, DCD, PACVD,DLC, thin-film coating or deposition technology, nano-film technology,single atom thick coating technology, sol-gel, solvent coating, aqueouscoating, and/or the like. In some embodiments the material, treatment,coating, layer, or function is applied or added by a solvent-freemethod, a binder-free method, or a solvent and binder free method. Inother selected embodiments, the layer is applied in the presence of abinder and/or solvent which may be subsequently removed post-process.

In accordance with at least selected embodiments, a porous membrane witha porous or ionically conductive coating or layer is provided as abattery separator in a lead acid battery and may improve the cycle life,cranking ability and high charge acceptance of the battery.

In accordance with at least particular embodiments, the batteryseparators described herein are directed to a multilayer or compositemicroporous membrane battery separator which may have excellentoxidation resistance and are stable in a lead acid battery system. Inaccordance with at least other selected embodiments, the presentinvention is directed to a battery separator having a layer whichincreases oxidation resistance, improved oxidation resistance in thepresence of metal ion contamination such as chromium ions, reduces acidstratification, improves surface conductivity, improves chargeacceptance, increases stiffness, runnability and processability, and/orincreases surface wettability. One of the methods used in polymericseparators to provide oxidation resistance is through sacrificialoxidation of residual oil. Oil (plasticizer) such as mineral oil is usedas a pore forming agent during wet process formation of polyethylene(PE) separators. When residual oil is left behind on the separator, itmay act as a sacrificial oxidizing species. Residual oil can be presentin the separator matrix generally at a concentration of from about 8% to20% by weight. The agent/oil acts as a sacrificial agent or componentand oxidizes before the polyethylene, thereby reducing the rate at whichthe separator itself is oxidized. However upon oxidizing, the sacrificedoil or material can be released from the separator and may manifest as adark or black residue or film on top of the electrolyte. Also, a layerof oxidation resistant material might replace a few percentage of oil inthe separator membrane and thereby reduce black residue issues.

In accordance with at least selected embodiments, aspects or objects,the present application or invention may address the above mentionedneeds or issues, and/or may provide at least one coating, layer, ormaterial on at least one surface, rib, side, or portion of a polymericmicroporous membrane. In accordance with at least selected embodiments,described are coatings, layers, films, treatments, depositions, ormaterials which impart improved oxidation resistance, reduced blackresidue, improved wettability, improved surface conductivity, and/orincreased stiffness to the separator. In accordance with at leastselected embodiments, described are batteries, particularly lead acidbatteries, having improved cycle life, charge acceptance, and/or reducedacid stratification.

In accordance with at least selected embodiments, disclosed are methodsfor preparing a porous membrane having a coating, layer, or materialthat may impart one or more of the above-mentioned desirable properties,performance, or characteristics. In some embodiments, the coating,layer, or material includes one or more layers of electricallyconductive or electrically insulating materials, for instance silica,alumina, metals, metal oxides, conductive carbon materials, cellulose,mixtures thereof, multiple layers, and/or the like.

Oxides are typically electrically non-conducting: such as, silica,silicon oxides, alumina, and aluminum oxides (silica is the common termfor silicon oxide, and alumina is the common term for aluminum oxide).

Metal, metal oxides, and carbon can all be electrically conductive orpartially conductive or semiconductive.

Separators are typically electrically nonconductive (insulators) but areporous and wet with electrolyte and allow ionic conductivity therethrough during charge and discharge of the battery. Certain materialsmay be electrical insulators (nonconductive) but may be thermallyconductive (such as alumina).

In certain selected embodiments, the coating, layer, or material isprovided on the surface of the porous membrane which faces the positiveelectrode, and in other embodiments, the coating, layer, or material (ora different coating, layer, or material) is provided on the surface ofthe porous membrane which faces the negative electrode. In certainembodiments, the coating, layer, or material (or a different coating,layer, or material) is provided on both surfaces (or sides, top andbottom sides, positive and negative faces) of the porous membrane orseparator. In some selected embodiments, the porous membrane is providedas an envelope or sleeve, and the coating, layer, or material may be onthe outer surface, inner surface, or on both surfaces of the envelope orsleeve.

In certain selected embodiments, provided is a layer for or on a side,surface, rib, or portion of a microporous battery separator membrane,such as in a lead acid battery, wherein the layer is possibly preferablyoxidation resistant (more resistant than the base film, substrate ormembrane) and is present on at least the side of the separator membranewhich faces the positive electrode, for instance, at the interface ofthe separator and the positive electrode (or glass mat adjacent thepositive electrode or plate or PAM), and that may also be stable up to acell potential of at least about 2.1, 2.2, 2.5, or 2.7 V (volts), orhigher in certain lead acid batteries or cells.

In accordance with certain embodiments, the separator membrane describedherein is directed to a microporous battery separator membrane having atleast one layer or deposition containing at least one material such assilica, silicon oxides, alumina, aluminum oxides, metals, metal oxides,conductive carbon materials, mixtures or blends thereof, and/or thelike, where the thickness of the deposition or layer is (or depositionsand/or layers are) in the range of 0.1 μm to 250 μm. A microporousmembrane in a lead-acid battery, having at least one layer containing asilica, silicon oxides, alumina, aluminum oxides, metals, metal oxides,conductive carbon materials, cellulose, cellulosic materials, mixturesor blends thereof, and/or the like can result in a separator having thesame or better targeted performance, characteristics or properties asseparators with residual oil, that are coated with other materialsand/or that do not have such a layer or coating.

A coating material used herein may be inert or reactive. Reactivematerial may undergo an initial reaction, for instance in the presenceof oxygen, electrolyte, electromagnetic radiation (example UV) orthermal energy inputs, which causes a chemical change either throughoutor at the surface of the coating or layer. The coating, layer, ormaterial on the substrate or membrane may be the deposition or coatingprocess starting material or may be a reacted (altered) material whichis or makes up the coating or layer on the membrane surface. Also, thecoating or layer may vary in concentration of the desired material (mayhave a gradient in concentration or density towards or away from thesurface). In certain selected embodiments, the coating or layer, asdescribed herein, may be very thin and contributes very littleadditional thickness to the overall thickness of porous membrane orsubstrate yet may provide equivalent oxidation resistance and/orstiffness as a much thicker oxidation resistant porous membrane. Incertain embodiments, the coating or layer, as described herein, may be amulti-stack layer formed by different materials. In certain selectedembodiments, the inventive separators contain substantially lessprocessing oil than conventional separators, because the inventivecoating layer reduces the need for a sacrificial agent to preventseparator oxidation. In certain selected embodiments, the separatorscontain substantially little or no processing oil, or no processing oilat the surface.

In certain selected embodiments, the inventive coating, layer, material,and/or the like can increase the wettability of the separator.Traditional polyolefinic separators typically have relativelyhydrophobic surfaces due to the crystallinity and polymer condensationthat occurs at the surface of traditional separators. In certainselected embodiments, the inventive coating material is a porous,hydrophilic material which optionally penetrates the surface of thepolymeric hydrophobic separator. See FIGS. 7 and 7A. However, thesurface alone can be hydrophilic due to coating material penetration orthe energetic beam or ion beam plasma, such as in physical vapordeposition (PVD), might make the coating component to embed itself ontothe surface forming a graded interface, this can contribute to betteradhesion of coating to the substrate, and/or it can form extendedinterface with better properties, such as hydrophilicity of thehydrophobic surface of the porous separator membrane or substrate,thereby increasing the wetting rate (of water or sulfuric acid) of thetreated, coated or modified separator. In some instance, the penetrationoccurs concurrently with the application of the coating to the porousmembrane, and in other embodiments, the penetration is achieved bycompression, calendering, thermal treatment to aid interfacial diffusionor other physical means after the coating material or deposition hasbeen applied. One possible coating material or component is cellulosicor cellulose, especially or possibly preferably a cellulose coating ormaterial on the positive side of the substrate or separator (the sidefacing the positive plate or electrode).

In at least certain embodiments, the inventive coating material may beelectrically conductive and may provide enhanced current distributionacross a polymeric microporous membrane. Such enhanced distribution canimprove electronic interaction with active material or PAM like PbO₂,thereby improving the speed at which lead sulfate (is formed) or isreduced, and thus improve the ability of the battery to receive a higherrate of charge (i.e., improve charge acceptance). By having a partiallyelectrically conductive insulating film (such as silica or alumina) onthe surface of an insulating polymeric film, the ionic conductivity fromPbO₂ to separator is expected to happen with ease. Having one or morelayers or coatings as an interface to reduce the barrier to ionicdiffusion should improve surface conductivity, charge acceptance, andcycle life. Such inventive coatings or layers may reduce the interfacebarrier between the conductive positive plate's Positive Active Material(PAM) and the insulative polymeric separator membrane or substrate. Forexample, it is contemplated to add carbon, metal, conductive material,or semiconductive material on the polymeric base membrane or film orover a silica coating or layer on the polymeric base membrane, substrateor film (transition layer or layers).

Various ceramic particle-containing coatings, ceramic coatings,inorganic coatings, organic coatings, inorganic and organic coatings,and/or polymeric coatings for microporous battery separator membranesmay provide improvement in safety, battery cycle life and/orperformance. Such coatings may include one or more polymers, inorganicor organic polymers or polymeric materials, polymeric binders, one ormore types of inorganic or organic particles, inorganic ceramicparticles and a water based or a non-aqueous solvent. Such coatings maybe applied using various technologies such as, but not limited to, PVD,CVD, sol-gel, dip coating, knife, gravure, curtain, spray, etc.

There is a need for improved battery separators which address some orall of the foregoing needs, issues or problems. For instance, there is aneed for batteries, especially lead acid batteries, with improved chargeacceptance and/or reduced acid stratification. There is a need forbattery separators with improved wettability, improved surfaceconductivity, improved oxidation resistance, and/or increased stiffness.There is a need for manufacturing processes which allow the rapidproduction of battery components, including separators, with reducedrejection rates of finished separators.

In at least certain embodiments, the coating, as described herein, mayreact with either atmospheric oxygen or electrolyte (sulfuric acid) toform a passivation layer. This passivation layer may be resistant tooxidation and may provide an additional protective layer on the surfaceof the reactive metal, for example, aluminum that may prevent oxidation.Once the passivation layer has formed, a higher level of oxidationstability for the improved separator may be achieved. In otherembodiments, the passivation layer may be obtained by subjecting thecoating layer to thermal, UV or other energy inputs.

In accordance with at least selected embodiments, the presentapplication or invention is directed to novel or improved porousmembranes or substrates, separator membranes, separators, composites,electrochemical devices, batteries, methods of making such membranes orsubstrates, separators, and/or batteries, and/or methods of using suchmembranes or substrates, separators and/or batteries. In accordance withat least certain embodiments, the present application is directed tonovel or improved microporous membranes, battery separator membranes,separators, energy storage devices, batteries including such separators,methods of making such membranes, separators, and/or batteries, and/ormethods of using such membranes, separators and/or batteries. Inaccordance with at least certain selected embodiments, the presentinvention is directed to a separator for a battery which has anoxidation protective and binder-free deposition layer which is stable upto at least 2.1, 2.2, 2.5, or 2.7 volts, or even higher in certainlead-acid batteries or cells.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a schematic vertical cross-section view of a conventionalpositive plate and adjacent battery separator, such as a microporous PEmembrane separator.

FIG. 2 is a schematic vertical cross-section view of a positive plateand an inventive functionalized separator with at least one functionalcoating, material, layer, or deposition on at least one side of a poroussubstrate, membrane or film, such as a microporous PE separator membraneor membrane separator.

FIG. 3 is a schematic vertical cross-section view of a positive plateand another inventive functionalized separator with at least twofunctional coatings, layers, depositions, and/or materials on at leastone side of a porous substrate, membrane or film, such as a microporousPE membrane separator. For example, Coating A may be carbon or alumina,and Coating B may be silica.

FIG. 4 is a schematic vertical cross-section view of a positive plateand yet another inventive functionalized separator with at least onefunctional coating, layer, deposition, and/or material on each side of aporous substrate, membrane or film, such as a microporous PE membraneseparator. For example, Coating C may be carbon, silica or alumina, andCoating D may be carbon or silica.

FIG. 5A is a table of non-limiting exemplary embodiments to be read inconjunction with the following description.

FIG. 5B is another table of non-limiting exemplary embodiments to beread in conjunction with the following description.

FIG. 6 is a schematic representation of a positive plate and aseparator.

FIG. 7 is a schematic representation of an inventive coated or treatedseparator with a surface coating, layer or treatment on one side.

FIG. 7A is a schematic representation of an enlarged portion of FIG. 7with an associated concentration graph showing the inventive coated ortreated separator with a surface coating or treatment on one side withthe coating or treatment material penetrating into the separator film orsubstrate and with a higher material concentration toward the outersurface of the coating, layer or treatment.

DETAILED DESCRIPTION

Embodiments of the claimed invention will now be discussed in detail.Certain terms and phrases shall be used as they are commonly known inthe art and/or as defined below.

Oxidation Resistance—The oxidation zone in a lead acid battery is at theinterface between the positive electrode, which is either a lead or alead-alloy grid pasted with positive active material (PAM), which may bePb02, and the electrolyte, which may be sulfuric acid. This oxidationzone is of the order of several hundred μm and extends into theelectrolyte where the separator is placed. It is evident that theseparator will be subjected to oxidation if it is in contact with thepositive electrode. In at least one embodiment, it is believed necessaryto provide oxidation resistance as one of the preferred characteristicsof the inventive separator. Polymers in general are not oxidationresistant. Different methods or layers are disclosed herein to provideoxidation resistance to a polymeric separator.

Sacrificial Material in the Separator—Polyethylene Separators are thepredominate material used in flooded lead acid batteries on a world-widebasis. In order to protect the polyethylene from oxidation attack whichoccurs in the lead acid battery, residual pore forming agent or oil isleft in the separator matrix up to 8% to 20% by weight. The oil will actas a sacrificial material and oxidize before the polyethylene. Howeverupon oxidizing, the oil is likely to be released from the separator andmay manifest itself as a black film or residue on top of theelectrolyte.

Glass Mat as an Interlayer—A thin layer of glass fiber mat may beattached or placed loosely between the polymeric separator and positiveelectrode. Glass is not oxidized by electrochemical potential or acid inlead acid batteries. This glass mat is in contact with positiveelectrode and does not undergo oxidation like polymer.

The present invention may add coatings as a means to, for example,improve the oxidation resistance of the PE separator, to replace theglass mat, or in addition to the glass mat that will allow for the oil,which is a pore forming agent, to be removed or greatly reduced and thusminimize the possible occurrence of black residue generation, to reducethe barrier to ionic diffusion, to increase surface conductivity, toenhance or facilitate charge acceptance, to reduce acid stratification,and/or the like. The coating may include polymer, binder, particles,fibers, and/or the like.

Stiffness or Processability—When producing automotive batteries, the PEseparator typically envelops or pockets, either the positive and/ornegative plate. This enveloping is done with automated equipment in acontinuous fashion. Traditionally, the separator has not been thetypical failure mode of automotive batteries, therefore the thickness ofthe separator has decreased over the years such that automotive batterymanufacturers have migrated from 250 μm down as low as 150 μm backwebthickness. As the bending stiffness is related to the cube of thethickness, such that a 30% reduction in thickness is likely to result ina 70% decrease in bending stiffness, the bending stiffness has decreasedsubstantially and the separator has become more of a challenge toprocess on existing equipment. This also increases the propensity forinadvertent folds and creases such that more product is rejected at theautomated equipment or that the running speeds have to be substantiallyreduced, which reduces productivity. Therefore, the present inventionmay also provide a means to go thinner, increase running speed, or forimproving bending stiffness, and/or a method of improving bendingstiffness of the separator, or any combination thereof.

Surface Conductivity—The electrical current is carried into the activematerial (PAM or NAM) via the positive or negative grid. It is knownthat the active material extends the plate grid either vertically,horizontally or laterally, or even into the depth of the electrode andoccupies different distances from grid. Therefore, the rate ofconversion of active material will not be uniform but likely is afunction of distance from the current collector. Therefore, the idea isto make the surface of the separator or associated laminate conductiveso that the electrons will have alternative paths to flow and react withthe active material. To the degree of which this can be achieved therereflects more efficient use of the active material in the energy storagereactions in both speed of conversion and degree of utilization.Therefore, a means and method for improving the charge acceptance of thebattery via modifications to the separator is described herein.

Acid Stratification—When lead acid batteries are deeply discharged thegravity of the electrolyte will decrease as the sulfuric acid is also aparticipant in the energy storage reactions. Upon recharging, puresulfuric acid will be created at the surface of the electrodes, whichwill be heavier than the bulk electrolyte gravity. As this boundarylayer of sulfuric acid is created at the electrode surface, it willcreate a boundary layer of which only the outer layers of sulfuric acidwill diffuse into the bulk electrolyte, while the remaining boundarylayer will be subjected to gravity and collect in the bottom of thebattery. As a battery is overcharged, gas bubbles will nucleate and riseto the top of the battery and carry some sulfuric acid to the top, thuscreating a mixing effect within the battery to at least partiallyovercome acid stratification. If the battery is not sufficiently overcharged, the stratified acid will be of detriment to the electrochemicalperformance of the battery going forward for it is inside the batterybut not at the right place, or spread about properly, in order to reactwith the entirety of the active material. Therefore, embodiments of thepresent invention provides a means for, and/or a method for reducing orbreaking the boundary acid created at the electrode surface, and/orallowing for acid mixing, and/or preventing acid stratification withoutthe use of overcharging and resultant gas evolution.

Improved Separator Wetting—It has been found that the surface of the PEseparators often are reasonably hydrophobic as they have polymer richsurface due to the nature of crystallinity and polymer condensation.This polymer rich layer may only be a few μm thick and once it ispenetrated the highly porous separator matrix beneath it is sufficientlyhydrophilic. Due to this situation, hydrophilic surfactants are oftensupplied to the separator surface or matrix to overcome this situation.In preferred embodiments, means for and/or alternative methods forwetting the surface of the separator matrix are provided.

All of the above mentioned embodiments of the present invention mayshare one common thing, which is forming, coating or depositing on tothe surface of the separator or laminate a layer (or layers) offunctional material to enhance the performance of the separator and thebattery of which the separator is placed, battery production, and/or thelike, and any combination thereof. Therefore, it is unexpectedlyconceived that various functional materials can be applied by vapordeposition, chemical deposition, solvent coating, aqueous coating andvarious combinations to the lead acid battery separator adjacent thePAM, NAM, or both, and with or without a glass mat. In certainembodiments, it is preferred that the added layer or layers may be inthe range of 0.1 μm to 250 μm, possibly preferably approximately 5 μm upto approximately 75 μm each or combined.

The coating can be a mixture of fibers, such as glass fibers, andparticles, such as silica, where by the glass fiber resists acidstratification in addition to oxidation. This can be achieved by coatinga sol-gel of material mixture containing glass fibers, silica, andbinder, and dispersing medium or solvent by roller or spray coating, andthe dispersing medium (e.g., water) may then be dried off. The binderwill bond the composite material together and with the substrate.

Oxidation Resistance and Black Residue—As precipitated silica isinherently porous in structure and inert against oxidative attack thatwould be found in a lead acid battery, it is proposed to deposit a thinlayer of silica on the surface of the separator or polymer membrane orsubstrate. It may be preferred that this silica be deposited in such amanner that the resulting sub-structure will still be porous andinherently adhered to the separator surface.

In application, the backweb, ribs, and/or the substrate mayinadvertently come in contact with the positive electrode. Duringcharging, and especially during overcharging, at the surface of theelectrode nascent oxygen or oxidizing species will be generated. As theywill come in contact with the separator, the bare polymeric separatorsurface may be oxidized, and especially the polymer which is what bindsthe separator constituents together. Given enough time these oxidizingspecies may actually create splits and cracks in the separator which mayultimately allow for electronic conductive paths between the positiveand negative electrodes, which can short the battery.

With an oxidative resistance layer of silica on the separator surface,many actions can be taken. First, the residual pore forming agent or oilmay be greatly reduced for it will may no longer be needed to protectthe polymer as that function will have been switched to the silicalayer. With a reduced residual pore forming agent present in theseparator, the propensity for black residue may decrease. With improvedoxidation resistance, the substrate or backweb thickness may further bereduced without fear of failure due to oxidation, cracks, splits, tears,or any combination thereof.

Stiffness, Runnability and Processability—The bulk of lead acid batteryseparators are three dimensional structures which include a substrate orbackweb at a given thickness and a three dimensional shape such as acontinuous trapezoid or rib protruding off the substrate surface(s). Dueto this arrangement, the lowest resistance to bending is found in theperpendicular direction to the ribs. As the separators are typicallysold in roll form, if very thin, they may be prone to folding, wrinklingor becoming skewed as the substrate is distorted across the width orcross machine direction (CMD) of separator. One method to improve theCMD bending resistance or stiffness is to deposit a material with a lowdegree of bending resistance or something that is semi-rigid. Oneembodiment deposits a layer of carbon or silica and the resultantnetwork would not be as prone to bending but actually be substantiallyrigid. This rigidity could be enhanced by the degree of packing of theindividual particles and thickness of the layer or layers deposited onthe substrate.

One possibly preferred embodiment is to deposit a continuous stiffeninglayer on either side of the separator (or both sides) regardless ofwhether the coating faces the negative or positive electrode. Stiffnesscan also be enhanced even if a layer of these materials are depositednot in a continuous layer but in a stripped or cross hatched pattern.

Improved Separator Wetting—To improve the separator wetting in theabsence of surfactants it is proposed to deposit on the surface of theseparator a thin layer of highly porous silica. This deposited silica,may require some additional calendaring forces to actual penetratethrough the rich polymer layer so as to improve the wetting rate of theseparator.

Surface Conductivity—To improve surface conductivity, it is foreseen todeposit carbon structures (e.g. graphite, graphene, carbon, CNT, etc.)that are sufficiently conductive, onto the surface of the separatorfacing the negative electrode, or on ribs facing the positive surface,or on a laminate, or AGM separator that is in direct contact with thepositive plate. As the lead acid battery is discharged, a layer of leadsulfate is formed at the electrode surface which is fairlynon-conductive in relation to the surrounding lead. As theaforementioned materials with a conductive layer will be in contact withthe electrodes, this will allow any surface charge to be transferred viaconductive paths that are now found on the separator and thus reduce thesulfate layer in a more efficient manner. Here it is important to notethe paths of conductance are being created mainly in the X and Y planeof the separator and not all the way through the Z plane. If electronicconductivity is achieved through the Z plane, then there will beelectronic conductance and the separator will cease to perform itsfunction as this will short the battery. By creating alternative pathsof conductance on the X and Y plane, it is foreseen to improve the speedat which lead sulfate is reduced and thus improve the ability to receivea higher rate of charge which is commonly referred to as chargeacceptance.

This layer of conductivity can also be applied to the ribs or laminatestructure such as in pasting paper, a retainer mat, an AGM separator, ora gauntlet, all of which come in intimate contact with the positiveelectrode. As the positive active material on the plate is converted atdifferent rates, depending on distance from the source of the currentcollector, some portions of the plates will be fully charged quickly andgo into gassing while other portions of active material will remainundercharged and need more current. Thus, some portion of the currentmay be wasted as gassing starts and cause higher rates of positive gridcorrosion. By providing alternative paths of current distribution to thepositive grid, current crowding is eliminated, the conversion willbecome more efficient resulting in less gassing and lower grid corrosionrates. These alternative paths of current distribution are from theconductive layers, such as, for example, carbon structures, that are nowon the separator ribs, AGM separator, or the laminate structure that arein direct contact with the positive electrode. The conductive materialcould easily contact to the positive paste (PAM) during formation ofbatteries resulting in enhancing conductive paths and reducing oreliminating the interface barrier between the separator and the positivepaste (positive plate).

Acid Stratification—To prevent acid stratification, the boundary layerof sulfuric acid that is being formed at both positive and negativeplates during charging may be broken up. Therefore, it is foreseen thatwhatever material is in contact with the plate surface, negative orpositive, has a deposit a thin layer of porous silica. As this silicalayer will be inherently porous and have a very high surface area, theacid will rapidly diffuse allowing it to readily mix with the bulk ofacid. As this silica layer may be in direct contact with the platesurface, it will serve also to mechanically interrupt the laminar flowof the boundary of acid to be acted upon primarily by gravity.

Therefore, one could foresee that this silica layer may be deposited onthe surface of the separator, or on the ribs, AGM, a laminate structurethat is in direct contact with the plates, such as pasting paper,retainer mats, or gauntlets, or any combination thereof.

The material, treatment or layer can be applied by vapor deposition,chemical deposition, vacuum assisted methods, PVD, CVD, TD, DCD, PACVD,DLC, thin-film coating or deposition technology, nano-film technology,single atom thick coating technology, sol-gel, solvent coating, aqueouscoating, and/or the like, or any combination thereof. For example:

PVD: Physical Vapor Deposition—atoms are dislodged from a metal or alloyor a composite target using a high energy beam and deposited on thesurface of interest. Atoms escape the target surface in ionized vaporform. Different energy sources are possible, such as electron beam,thermal energy, electric resistance heating of surface, pulsed laser,plasma discharge, etc. All these methods are vacuum assisted.

CVD: Chemical Vapor Deposition—A reactive precursor containing thematerial to be deposited in some chemical form reacts or decomposes onthe substrate surface and forms a deposit. The volatile by-products ofprecursor decomposition or reaction will be pumped out of the depositionchamber. Precursors are gaseous species, chemically designed to form thedeposit of the right chemical nature on the surface. The unneededportion of precursor leaves the chamber. Depending upon the chamberpressure, the CVD method is called atmospheric pressure (APCVD), lowpressure (LPCVD) and ultrahigh vacuum (UHVCVD). Plasma enhanced (PACVD)uses plasma to enhance the reaction of the precursor. Other variationsto fit the needs of deposition are also possible.

DCD: Dynamic Compound Deposition—Coatings are formed by a lowtemperature process in which a dry film is formed on the surface. Thedeposition is based on the principle of in-situ mechanical activationand chemical transformation of the surface. This can be assisted by PVDor CVD or combinations thereof. Micro and macro structures can bedeveloped on the surface using this process. One can envision formingjust ribs by this process or forming a coating over the entire surface.

Thermal or Thermoreactive Deposition (TD) is a high temperaturedeposition process for producing high temperature stable materials suchas oxide, carbide, etc.

DLC may be diamond like carbon. Diamond like carbon is an insulating ordielectric material.

Out of the many property sets required in separators, some are bulk andothers are surface properties. At least selected embodiments of thisinvention may address surface related properties at the surface, and indoing so may reduce the requirements or cost of the bulk. For example,oxidation resistance is required at the surface of contact with positiveplate, so we can reduce oxidation resistant components throughout thebulk. Also, properties such as surface conductivity, oxidationresistance, acid stratification reduction, improved wettability arerequired at the surface, so we can address these at or on the surface,for example, by coating.

Surface coatings comprising of polar materials such as silica, alumina,etc. by any method such as chemical vapor deposition, atomic layerdeposition (ALD), sol-gel coating, roller coating, etc. may provide theneeded performance in terms of reducing acid stratification, improvingoxidation resistance, increasing wettability, higher surface ionicconductivity, and so on. Precise thickness to the desired or requiredlevel can be done using these methods. High level of purity can also beaccomplished by these methods.

By having carbon or any other conductive or semiconductive layer or acombination of conductive and polar layers (silica and carbon togetherfor example), one can envision improving charge acceptance.

Vapor deposition processes are vacuum or low pressure assistedprocesses. Having oil in the separator may result in blistering ofcoatings as oil tends to ooze out of pores in vacuum. By having a dryfilm coated with the inventive layers, this issue is eliminated. Also,adhesion of the layer to the substrate may not be a big issue as theseparator also contains silica which will help with bonding the polaroxide coatings to the substrate.

Advantages of at Least Certain Embodiments of the Invention

1. Providing functions where it is needed through surface layers helpsin isolating the issues and solving by multiple methods.

2. Improving surface properties will not only improve separatorperformance but extends to improving charging and dischargingperformance, charge acceptance, etc. of batteries.

3. A myriad of coating methods and materials are possible. Even glassfibers, cellulose fibers, carbon fibers, conductive carbon fibers,and/or the like can be coated on the surface of separators using rollercoating with small amount of binders. This can be applied as a rib byusing screen printing methods through a mask.

Non-Limiting Examples

a. Same Material Coated on Both Sides

The polymer substrate may be coated on both sides with a conductivecarbon coating applied by roller coating. Desired coating thickness maybe from approximately 1 μm to approximately 20 μm. This may improve thesurface conductivity of the surface, reduce current crowding, improvecurrent distribution, and improve charge acceptance of batteries builtwith such separators. Carbon, being porous, may also provide retentionof acid reducing acid stratification on both electrodes.

b. Different Coating on Each Side

Example: Alumina on Positive Side and Silica on Negative Side

Aluminum may be deposited on the separator by physical vapor depositionin the presence of oxygen. Due to the presence of plasma and oxygen,aluminum at the substrate surface becomes alumina and deposits on thesurface. The thickness of the coating is preferred to be of the order ofapproximately 2 μm to approximately 10 μm. Alumina, being highly polar,is hypothesized to reduce the barrier to diffusion of ions at thepositive interface between electrode and separator. Alumina, beingporous, reduces the acid stratification. Alumina also could potentiallylock (bind) metal ions that are deleterious to the performance of leadacid batteries, such as Sb, Cr, Ni, Mn, etc. Silica on the negative sidecan be deposited by sol-gel methods using precipitated silica in a smallquantity of polymeric binder, such as, for example, acrylic resin. Aroller coating method may also be used to get a thin uniform coatingpreferably of the order of approximately 1 μm to approximately 20 μm orhigher. High surface area silica and alumina could potentially preventmigration of harmful ions, reduce acid stratification and increasestiffness of films and puncture resistance. Alumina on the positive sideprovides oxidation resistance. Therefore, the polymeric separator mayhave less oil, which is a sacrificial oxidizing medium in a polyethyleneseparator, which in turn may reduce the propensity to black residueformation, reduce cost, etc.

c. Two or More Layer Coatings

Three or more layers: Carbon (spray coating)/Alumina (reactivePVD)/silica (sol-gel)/separator/carbon (spray coating) from positive tonegative plate facing sides

Similar methods as above may be employed. Silica may preferably be firstcoated on one side of separator. Alumina may then be deposited on top ofthe silica. Carbon may then be deposited on both sides. This enablesboth surface conductive properties and hydrophilic properties fromalumina and silica. Alumina and silica provide oxidation resistance tothe polymeric separator.

d. Gradient Coating (Coating Surface is High in Carbon, and Near BaseFilm Coating is High in Alumina)

Carbon/Alumina-Carbon Composite/Separator

A separator may first be coated with alumina using reactive physicalvapor deposition in oxygen to get approximately 2 μm to approximately 4μm. The target is changed to an Al—C composite target which whensputtered gives rise to a different loading of carbon in Alumina. Thisprovides a gradation in concentration of carbon with low amounts closeto separator. The top most layer of carbon is deposited by CVD. By doingthis, a gradation in concentration of carbon is accomplished with 100%carbon on the surface to approximately 50% carbon at the intermediateregions to approximately 0% Carbon close to the PE separator surface. Bydoing this, ionic conductivity may be extended, a higher porosity may beachieved for capturing contaminants such as Cr, Mn, etc., and a reducedneed for oil which reduces black residue.

e. Possible Two Layer Coatings

Carbon on alumina on separator.

Carbon by CVD or roller coating. Benefits: surface conduction, oxidationresistance, reduced acid stratification, improved charge acceptance.

Alumina by reactive PVD: increased diffusion of ions through separator.Reduced migration of harmful ions such as Cr, Sb, Mn from positive tonegative electrode.

f. Possible Gradient Coatings

Carbon gradient is preferred because of the electrical conductivity itprovides.

Alumina coating is also preferred as it has high oxidation resistance.

g. Possible Positive Plate Side Coatings

Preferred positive side coating is something that provides highoxidation resistance in deep cycle flooded lead acid batteries.Conductive carbon that provides high surface conduction in Starting,Lighting, Ignition (SLI) batteries to provide high Cold Cranking Amps(CCA) and dynamic charge acceptance.

h. Possible Negative Plate Side Coatings

The negative side of the separator does not get oxidized. However, thepresence of porous coatings on the top reduces acid stratification.Carbon provides improved interfacial conduction on the negative side andmay improve capacity.

i. Other Possibly Preferred Examples

A coating of Nafion (a sulfonated tetrafluoroethylene basedfluoropolymer-copolymer) or Polytetrafluoroethylene (PTFE) which may beused in flow batteries may prevent diffusion of vanadium, chromium,iron, etc. This property is very useful to lead acid batteries that maybe plagued by elements like Antimony (positive grid is made of Pb—Sb fordeep cycling performance), Chromium that may come from make-up acid indry charge batteries, iron from the silica used in PE separators, etc.These elements are electrochemically active in lead acid batterypotential regimes and may induce oxidation of separators (Cr, Fe) orincrease hydrogen gas evolution (Sb) due to reduced hydrogen overvoltageof antimony when deposited on the negative plate. Nafion may preventdiffusion of these ionic species. A thin coating of thickness aroundapproximately 2 μm to approximately 10 μm is thought to be able toprovide the needed barrier properties for the diffusion of these ions.If this material is deposited on top of an AGM, it opens up a newpossibility of using AGM type separators in antimony containing systems.Similar functions are expected from materials such as polyethylene oxidewith sulfonic acid containing side chains or other complexing groups asside chains.

j. Cellulosic separators or paper separators are commonly used in drycharge batteries. Such separators are in general formed of four basiccomponents: cellulose fibers, phenol formaldehyde resin (Novolacs),wetting agent and cellulose binder. Cellulose imparts resistance tooxidation during formation and functioning of batteries. Inventive PEseparators can be coated with a layer of cellulose-binder mixture of theorder of 1 to 20 nm. The surface layer will impart the needed oxidationresistance to the PE separator in Cr or other metal containingenvironments such as those found in dry charge batteries.

k. Possible coatings to battery case, plates, glass mats, view device,and/or separator

A thin layer of glass fiber with a small quantity of organic binder(less than approximately 1%) may be deposited on top of a PE separatorby spray coating or roller coating, etc. The whole assembly is cured toform a thin layer glass fiber layer on top of the separator. The glassfiber has very high oxidation resistance and offers capillary forces toretain acid and prevent acid stratification.

Microporous Membranes

The inventive separator preferably includes a porous substrate ormembrane (such as a microporous membrane having pores less than about 1μm, mesoporous, or a macroporous membrane having pores greater thanabout 1 μm) made of natural or synthetic materials, such as polyolefin,polyethylene, polypropylene, phenolic resin, PVC, rubber, synthetic woodpulp (SWP), glass fibers, cellulosic fibers, or combinations thereof,more preferably a microporous membrane made from thermoplastic polymers.The preferred microporous membranes may have pore diameters of about 0.1μm (100 nm) or less and porosities of about 60%. The polymers may, inprinciple, include all acid-resistant thermoplastic materials suitablefor use in lead acid batteries. The preferred thermoplastic polymersinclude polyvinyls and polyolefins. The polyvinyls include, for example,polyvinyl chloride (PVC). The polyolefins include, for example,polyethylene, ultrahigh molecular weight polyethylene (UHMWPE), andpolypropylene. One preferred embodiment may include UHMWPE and a filler.In general, the preferred separator may be made by mixing, in anextruder filler, UHMWPE, and processing oil. In some embodiments, thepreferred separator may be made by mixing, in an extruder, about 30% byweight filler with about 10% by weight UHMWPE, and about 60% processingoil. In other embodiments, the filler content is higher, for instance,about 50%, 60%, 70% or 80% by weight. In other selected embodiments, theprocessing oil is present in an amount that is not more than 60%, 50%,45%, 40%, 35%, 30%, 25%, 20%, 15%, or 10% by weight. The mixture mayalso include minor amounts of other additives or agents as is common inthe separator arts (such as wetting agents, colorants, antistaticadditives, and/or the like) and is extruded into the shape of a sheet.

The microporous separator layer is preferably made of a polyolefin, suchas polypropylene, ethylene-butene copolymer, polyethylene-polybutadienecopolymer, polyethylene-polyisoprene copolymer and preferablypolyethylene, more preferably high molecular weight polyethylene, i.e.polyethylene having a molecular weight of at least 600,000, even morepreferably ultrahigh molecular weight polyethylene, i.e. polyethylenehaving a molecular weight of at least 1,000,000, in particular more than4,000,000, and most preferably 5,000,000 to 8,000,000 (measured byviscosimetry and calculated by Margolie's equation), a standard loadmelt index of substantially 0 (measured as specified in ASTM D 1238(Condition E) using a standard load of 2,160 g) and a viscosity numberof not less than 600 ml/g, preferably not less than 1,000 ml/g, morepreferably not less than 2,000 ml/g, and most preferably not less than3,000 ml/g (determined in a solution of 0.02 g of polyolefin in 100 g ofdecalin at 130° C.).

In accordance with at least one embodiment, the separator is made up ofan ultrahigh molecular weight polyethylene (UHMWPE) mixed with aprocessing oil and filler. In accordance with at least one otherembodiment, the separator is made up of an ultrahigh molecular weightpolyethylene (UHMWPE) mixed with a processing oil, additive and talc.The microporous polymer layer preferably comprises a homogeneous mixtureof 8 to 100 vol. % of polyolefin, 0 to 40 vol. % of a plasticizer and 0to 92 vol. % of inert filler material. The preferred filler is talc. Thepreferred plasticizer is petroleum oil. Since the plasticizer is thecomponent which is easiest to remove from the polymer-filler-plasticizercomposition, it is useful in imparting porosity to the batteryseparator.

In certain embodiments, residual processing oil may be removed afterextrusion by conventional methods, such as solvent washing, oven, or thelike. In certain selected embodiments, the final amount of processingoil that is present in the extruded polymer is no more than 20%, 18%,16%, 14%, 12%, 10%, 9%, 8%, 7%, 6%, 5%, 4%, 3%, 2%, 1% or 0.5% byweight.

In some instances, the preferred filler is dry, finely divided silica.However, the filler may be selected from the group consisting of:silica, fumed silica, mica, montmorillonite, kaolinite, asbestos, talc,diatomaceous earth, vermiculite, natural and synthetic zeolites, cement,calcium silicate, clay, aluminum silicate, sodium aluminum silicate,aluminum polysilicate, alumina silica gels, glass particles, carbonblack, activated carbon, carbon fibers, conductive carbon fibers, otherconductive fibers, cellulose fibers, charcoal, graphite, titanium oxide,iron oxide, copper oxide, zinc oxide, lead oxide, tungsten, antimonyoxide, zirconia, magnesia, alumina, molybdenum disulfide, zinc sulfide,barium sulfate, strontium sulfate, calcium carbonate, magnesiumcarbonate, and the like, and various combinations thereof. For example,a thin layer of fumed silica may be applied using organic solvents andcould potentially eliminate acid stratification and provide oxidationresistance. The thin layer of fumed silica may include carbon or othermaterials. For example, infiltrating fumed silica and cellulose fiberand binder together as film on top of PE membrane may hold the fumedsilica in place. Also, a thin layer of fumed silica may be applied onone side and a carbon layer may be applied on the other side, or a thinlayer of carbon may be applied over the thin layer of fumed silica.

The porous membrane used in various embodiments herein may be providedwith one or more additives or agents. One such additive that may bepresent in the polyolefin is a surfactant. Suitable surfactants includesurfactants such as salts of alkyl sulfates; alkylarylsulfonate salts;alkylphenol-alkylene oxide addition products; soaps;alkyl-naphthalene-sulfonate salts; dialkyl esters of sulfo-succinatesalts; quaternary amines; block copolymers of ethylene oxide andpropylene oxide; and salts of mono and dialkyl phosphate esters. Theadditive can be a non-ionic surfactant such as polyol fatty acid esters,polyethoxylated esters, polyethoxylated fatty alcohols, alkylpolysaccharides such as alkyl polyglycosides and blends thereof, amineethoxylates, sorbitan fatty acid ester ethoxylates, organosilicone basedsurfactants, ethylene vinyl acetate terpolymers, ethoxylated alkyl arylphosphate esters and sucrose esters of fatty acids.

In certain embodiments, the additive, agent or surfactant can berepresented by a compound of Formula (I)R(OR¹)n(COOM^(x+) _(1/x))m  (1)

in which

-   -   R is a non-aromatic hydrocarbon radical with 10 to 4200 carbon        atoms, preferably 13 to 4200, which can be interrupted by oxygen        atoms,    -   R¹ is H, —(CH₂)_(k)COOM^(x+) _(1/x) or —(CH₂)_(k)—SO₃M^(x+)        _(1/x), preferably H, where k is 1 or 2,    -   M is an alkali metal or alkaline-earth metal ion, H⁺ or NH₄ ⁺,        where not all the variables M simultaneously have the meaning        H⁺,    -   n is 0 or 1,    -   m is 0 or an integer from 10 to 1400 and    -   x is 1 or 2,

the ratio of oxygen atoms to carbon atoms in the compound according toFormula (I) being in the range from 1:1.5 to 1:30 and m and n not beingable to simultaneously be 0. However, preferably only one of thevariables n and m is different from 0.

By non-aromatic hydrocarbon radicals is meant radicals which contain noaromatic groups or which themselves represent one. The hydrocarbonradicals can be interrupted by oxygen atoms, i.e. contain one or moreether groups.

R is preferably a straight-chain or branched aliphatic hydrocarbonradical which can be interrupted by oxygen atoms. Saturated,uncross-linked hydrocarbon radicals are quite particularly preferred.

The use of the compounds of Formula (I) for the production of anadditive for various porous membrane described herein may also providesuch separators with effective protection against oxidative destruction.In some embodiments, porous membrane are preferred which include anadditive containing a compound according to Formula (I) in which

-   -   R is a hydrocarbon radical with 10 to 180, preferably 12 to 75        and quite particularly preferably 14 to 40 carbon atoms, which        can be interrupted by 1 to 60, preferably 1 to 20 and quite        particularly preferably 1 to 8 oxygen atoms, particularly        preferably a hydrocarbon radical of formula        R²—[(OC₂H₄)_(p)(OC₃H₆)_(q)]—, in which    -   R² is an alkyl radical with 10 to 30 carbon atoms, preferably 12        to 25, particularly preferably 14 to 20 carbon atoms,    -   P is an integer from 0 to 30, preferably 0 to 10, particularly        preferably 0 to 4 and    -   q is an integer from 0 to 30, preferably 0 to 10, particularly        preferably 0 to 4,    -   compounds being particularly preferred in which the sum of p and        q is 0 to 10, in particular 0 to 4,    -   n is 1 and    -   m is 0.

Formula R²—[(OC₂H₄)_(p)(OC₃H₆)_(q)]— is to be understood as alsoincluding those compounds in which the sequence of the groups in squarebrackets differs from that shown. For example according to the inventioncompounds are suitable in which the radical in brackets is formed byalternating (OC₂H₄) and (OC₃H₆) groups.

Additives in which R² is a straight-chain or branched alkyl radical with10 to 20, preferably 14 to 18 carbon atoms have proved to beparticularly advantageous. OC₂H₄ preferably stands for OCH₂CH₂, OC₃H₆for OCH(CH₃)CH₂ and/or OCH₂CH(CH₃).

As preferred additives there may be mentioned in particular alcohols(p=q=0; m=0) primary alcohols being particularly preferred, fattyalcohol ethoxylates (p=1 to 4, q=0), fatty alcohol propoxylates (p=0;q=1 to 4) and fatty alcohol alkoxylates (p=1 to 2; q=1 to 4) ethoxylatesof primary alcohols being preferred. The fatty alcohol alkoxylates arefor example accessible through reaction of the corresponding alcoholswith ethylene oxide or propylene oxide.

Additives of the type m=0 which are not, or only partially, soluble inwater and sulphuric acid have proved to be particularly advantageous.

Also preferred are additives which contain a compound according toFormula (I), in which

-   -   R is an alkane radical with 20 to 4200, preferably 50 to 750 and        quite particularly preferably 80 to 225 carbon atoms,    -   M is an alkali metal or alkaline-earth metal ion, H+ or NH₄+, in        particular an alkali metal ion such as Li+, Na+ and K+ or H+,        where not all the variables M simultaneously have the meaning        H+,    -   n is 0,    -   m is an integer from 10 to 1400 and    -   x is 1 or 2.

As suitable additives there may be mentioned here in particularpolyacrylic acids, polymethacrylic acids and acrylic acid-methacrylicacid copolymers, whose acid groups are at least partly, i.e. preferably40%, particularly preferably 80%, neutralized. The percentage refers tothe number of acid groups. Quite particularly preferred arepoly(meth)acrylic acids which are present entirely in the salt form. Bypoly(meth)acrylic acids are meant polyacrylic acids, polymethacrylicacids and acrylic acid-methacrylic acid copolymers. Poly(meth)acrylicacids are preferred and in particular polyacrylic acids with an averagemolar mass Mw of 1,000 to 100,000 g/mol, particularly preferably 1,000to 15,000 g/mol and quite particularly preferably 1,000 to 4,000 g/mol.The molecular weight of the poly(meth)acrylic acid polymers andcopolymers is ascertained by measuring the viscosity of a 1% aqueoussolution, neutralized with sodium hydroxide solution, of the polymer(Fikentscher's constant).

Also suitable are copolymers of (meth)acrylic acid, in particularcopolymers which, besides (meth)acrylic acid contain ethylene, maleicacid, methyl acrylate, ethyl acrylate, butyl acrylate and/or ethylhexylacrylate as comonomer. Copolymers are preferred which contain at least40 wt.-%, preferably at least 80 wt.-% (meth)acrylic acid monomer, thepercentages being based on the acid form of the monomers or polymers.

To neutralize the polyacrylic acid polymers and copolymers, alkali metaland alkaline-earth metal hydroxides such as potassium hydroxide and inparticular sodium hydroxide are particularly suitable.

The porous membrane can be provided in various ways with the additive oradditives. The additives can for example be applied to the polyolefinwhen it is finished (i.e. after the extraction) or added to the coatingmixture used to produce the porous membrane (for instance, duringpolymerization). According to one possibly preferred embodiment theadditive or a solution of the additive may be applied to the surface ofthe porous membrane or the surface of the coating. This variant issuitable in particular for but not limited to the application ofnon-thermostable additives and additives which are soluble in thesolvent used for the subsequent extraction. The coating need not gothrough extraction after coating. For example, after PE separator isformed through extrusion extraction process, this coating mixture ofmaterials and additive can be coated as film on the PE membrane with noextraction afterward, and if the additive coating precedes a conductiveor oxidation resistant, stiffness enhancing coating(s), the additivebeing polar material could increase the adhesion between the PEsubstrate and the top coating.

Particularly suitable as solvents for the additives according to theinvention are low-molecular-weight alcohols, such as methanol andethanol, as well as mixtures of these alcohols with water. Theapplication can take place on the side facing the negative electrode,the side facing the positive electrode or on both sides of the porousmembrane. For embodiments in which the coating layer is present on onlyone side of the porous membrane, the additive can be applied to thecoating layer, to the side to which the coating layer is not applied, orto both sides of the separator.

The additive can be present at a density of at least 0.5 g/m2, 1.0 g/m2,1.5 g/m2, 2.0 g/m2, 2.5 g/m2, 3.0 g/m2, 3.5 g/m2, 4.0 g/m2, 4.5 g/m2,5.0 g/m2, 5.5 g/m2, 6.0 g/m2, 6.5 g/m2, 7.0 g/m2, 7.5 g/m2, 8.0 g/m2,8.5 g/m2, 9.0 g/m2, 9.5 g/m2 or 10.0 g/m2. The additive can be presenton the separator at a density between 0.5-10 g/m2, 1.0-10.0 g/m2,1.5-10.0 g/m2, 2.0-10.0 g/m2, 2.5-10.0 g/m2, 3.0-10.0 g/m2, 3.5-10.0g/m2, 4.0-10.0 g/m2, 4.5-10.0 g/m2, 5.0-10.0 g/m2, 5.5-10.0 g/m2,6.0-10.0 g/m2, 6.5-10.0 g/m2, 7.0-10.0 g/m2, 7.5-10.0 g/m2, 5.0-10.5g/m2, 5.0-11.0 g/m2, 5.0-12.0 g/m2, or 5.0-15.0 g/m2.

The application may also take place by dipping the porous membrane orseparator in the additive or a solution of the additive and subsequentlyoptionally removing the solvent, e.g. by drying. In this way theapplication of the additive can be combined for example with theextraction often applied during polyolefin production.

The thickness of the porous membrane is preferably greater than 0.1 mmand less than or equal to 5.0 mm. The thickness of the porous membranecan be within the range of 0.15 to 2.5 mm, 0.25-2.25 mm, 0.5-2.0 mm, or0.75-1.5 mm. The porous membrane can be approximately 0.8 mm or 1.1 mmthick.

In certain selected embodiments, the backweb thickness of the porousmembrane is no more than 500 μm, 400 μm, 300 μm, 250 μm, 200 μm, 175 μm,150 μm, 125 μm, 100 μm or less. In various embodiments, the porousmembrane contains ribs. The preferred ribs may be 0.008 mm to 1 mm talland may be spaced 0.001 mm to 10 mm apart. For example, the ribs can be0.05 mm, 0.1 mm, 0.2 mm, 0.3 mm, 0.4 mm, 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm,0.9 mm, 1.0 mm, 1.2 mm, 1.4 mm, 1.6 mm, 1.8 mm, 2.0 mm, 2.25 mm, 2.5 mm,2.75 mm, 3 mm, 4 mm, 5 mm, 6 mm, 7 mm, 8 mm, 9 mm, or 10 mm apart. Insome embodiments, the ribs may be in a pattern such as they may be onone side of the separator layer or on both sides of the porous membrane,from 0 to 90 degrees in relation to each other. In certain selectedembodiments, the ribs are on both sides of the porous membrane, at anangle of 0, 45, or 90 degrees from each other. Various patternsincluding ribs on both sides of the separator layer may include negativecross-ribs on the second side or back of the separator.

In accordance with at least another object of the present invention,there is provided a porous membrane with ribs. The porous membrane canhave transverse cross-ribs on the opposite face of the porous membraneas the longitudinal ribs. In some embodiments of the present invention,the ribbed porous membrane can have a transverse rib height of at least0.005 mm, 0.01 mm, 0.025 mm, 0.05 mm, 0.075 mm, 0.1 mm, 0.2 mm, 0.3 mm,0.4 mm, 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm, or 1.0 mm. The ribbedporous membrane can have a transverse rib height between 0.005-1.0 mm,0.01-0.5 mm, 0.025-0.5 mm, 0.05-0.5 mm, 0.075-0.5 mm, 0.1-0.5 mm,0.2-0.4 mm, 0.3-0.5 mm, or 0.4-0.5 mm.

In some embodiments of the present invention, the ribbed porous membranecan have longitudinal rib height of at least 0.005 mm, 0.01 mm, 0.025mm, 0.05 mm, 0.075 mm, 0.1 mm, 0.2 mm, 0.3 mm, 0.4 mm, 0.5 mm, 0.6 mm,0.7 mm, 0.8 mm, 0.9 mm, 1.0 mm, 1.1 mm, 1.2 mm, 1.3 mm, 1.4 mm, or 1.5mm. The ribbed porous membrane can have a transverse rib height between0.005-1.5 mm, 0.01-1.0 mm, 0.025-1.0 mm, 0.05-1.0 mm, 0.075-1.0 mm,0.1-1.0 mm, 0.2-1.0 mm, 0.3-1.0 mm, 0.4-1.0 mm, 0.5-1.0 mm, 0.4-0.8 mmor 0.4-0.6 mm.

In some embodiments of the present invention, the ribbed porous membranecan have a sheet (substrate) thickness of at least 0.005 mm, 0.01 mm,0.025 mm, 0.05 mm, 0.075 mm, 0.1 mm, 0.2 mm, 0.3 mm, 0.4 mm, 0.5 mm, 0.6mm, 0.7 mm, 0.8 mm, 0.9 mm, or 1.0 mm. The ribbed porous membrane canhave a sheet (substrate) thickness between 0.005-1.0 mm, 0.01-1.0 mm,0.025-1.0 mm, 0.05-1.0 mm, 0.075-1.0 mm, 0.1-1.0 mm, 0.2-1.0 mm, 0.3-1.0mm, 0.4-1.0 mm, 0.4-0.9 mm, 0.4-0.8 mm, 0.5-0.8 mm or 0.6-0.8 mm.

In some embodiments of the present invention, the ribbed porous membranecan have overall thickness (positive rib+backweb+negative rib) of atleast 0.05 mm, 0.1 mm, 0.25 mm, 0.5 mm, 0.75 mm, 1.0 mm, 1.5 mm, 2.0 mm,2.5 mm, 3.0 mm, 3.5 mm, 4.0 mm, 4.5 mm, 5.0 mm, or 6.0 mm. The ribbedporous membrane can have a transverse rib height between 0.05-5.0 mm,0.1-5.0 mm, 0.2-5.0 mm, 0.5-5.0 mm, 1.0-5.0 mm, or 1.0-4.0 mm.

In some cases the ribs need not be present on one or both sides. Forexample, the separator, substrate or membrane may be a flat sheet oronly have ribs on one side.

With regard to at least selected embodiments of the present invention,the ribbed porous membrane can have the following:

1) Transverse Rib Height—preferably between about 0.02 to 0.45 mm, andmost preferably between about 0.075 to 0.3 mm.

2) Sheet (Substrate) Thickness—preferably between about 0.065 to 0.75mm.

3) Overall Thickness (positive rib+backweb+negative rib)—overallthickness of the separator between about 0.10 to 6.0 mm, preferablybetween about 0.20 to 4.0 mm.

The ribs may be serrated. The serrations may have an average tip lengthof from 0.05 mm to 1 mm. For example, the average tip length can begreater than or equal to 0.05 mm, 0.1 mm, 0.2 mm, 0.3 mm, 0.4 mm, 0.5mm, 0.6 mm, 0.7 mm, 0.8 mm, or 0.9 mm; and/or less than or equal to 1.0mm, 0.9 mm, 0.8 mm, 0.7 mm, 0.6 mm, 0.5 mm, 0.4 mm, 0.3 mm, 0.2 mm, or0.1 mm.

The serrations may have an average base length of from 0.05 mm to 1 mm.For example, the average base length can be greater than or equal to0.05 mm, 0.1 mm, 0.2 mm, 0.3 mm, 0.4 mm, 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm,or 0.9 mm; and/or less than or equal to 1.0 mm, 0.9 mm, 0.8 mm, 0.7 mm,0.6 mm, 0.5 mm, 0.4 mm, 0.3 mm, 0.2 mm, or 0.1 mm.

The serrations may have an average height of from 0.05 mm to 1 mm. Forexample, the average height can be greater than or equal to 0.05 mm, 0.1mm, 0.2 mm, 0.3 mm, 0.4 mm, 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, or 0.9 mm;and/or less than or equal to 1.0 mm, 0.9 mm, 0.8 mm, 0.7 mm, 0.6 mm, 0.5mm, 0.4 mm, 0.3 mm, 0.2 mm, or 0.1 mm. For embodiments in which theserration height is the same as the rib height, the serrated ribs mayalso be referred to as protrusions.

The serrations can have an average center-to-center pitch of from 0.1 mmto 50 mm. For example, the average center-to-center pitch can be greaterthan or equal to 0.2 mm, 0.3 mm, 0.4 mm, 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm,0.9 mm, 1.0 mm, 1.25 mm, or 1.5 mm; and/or less than or equal to 1.5 mm,1.25 mm, 1.0 mm, 0.9 mm, 0.8 mm, 0.7 mm, 0.6 mm, 0.5 mm, 0.4 mm, 0.3 mm,or 0.2 mm.

The serrations can have an average height to base width ratio of from0.1:1 to 500:1. For example, the average height to base width ratio canbe greater than or equal to 0.1:1, 25:1, 50:1, 100:1, 150:1, 200:1,250:1, 300:1, 350:1, or 450:1; and/or less than or equal to 500:1,450:1, 400:1, 350:1, 300:1, 250:1, 200:1, 150:1, 100:1, 50:1, or 25:1.

The serrations can have average base width to tip width ratio of from1000:1 to 0.1:1. For example, the average base width to tip width ratiocan be greater than or equal to 0.1:1, 1:1, 2:1, 3:1, 4:1, 5:1, 6:1,7:1, 8:1, 9:1, 10:1, 15:1, 20:1, 25:1, 50:1, 100:1, 150:1, 200:1, 250:1,300:1, 350:1, 450:1, 500:1, 550:1, 600:1, 650:1, 700:1, 750:1, 800:1,850:1, 900:1, 950:1, and/or less than or equal to 1000:1, 950:1, 900:1,850:1, 800:1, 750:1, 700:1, 650:1, 600:1, 550:1, 500:1, 450:1, 400:1,350:1, 300:1, 250:1, 200:1, 150:1, 100:1, 50:1, 25:1, 20:1, 15:1, 10:1,9:1, 8:1, 7:1, 6:1, 5:1, 4:1, 3:1, 2:1, or 1:1.

In some embodiments, the porous membrane can be perforated. Aperforation can be a row or line of substantially identically sizedholes. The rows or lines may be spaced 0.001 mm to 10 mm apart. Forexample, the rows can be 0.05 mm, 0.1 mm, 0.2 mm, 0.3 mm, 0.4 mm, 0.5mm, 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm, 1.0 mm, 1.2 mm, 1.4 mm, 1.6 mm, 1.8mm, 2.0 mm, 2.25 mm, 2.5 mm, 2.75 mm, 3 mm, 4 mm, 5 mm, 6 mm, 7 mm, 8mm, 9 mm, or 10 mm apart.

The perforations may have an average hole length of from 0.05 mm to 1mm. For example, the average tip width can be greater than or equal to0.05 mm, 0.1 mm, 0.2 mm, 0.3 mm, 0.4 mm, 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm,or 0.9 mm; and/or less than or equal to 1.0 mm, 0.9 mm, 0.8 mm, 0.7 mm,0.6 mm, 0.5 mm, 0.4 mm, 0.3 mm, 0.2 mm, or 0.1 mm.

The perforations may have an average hole width of from 0.01 mm to 1 mm.For example, the average hole width can be greater than or equal to 0.05mm, 0.1 mm, 0.2 mm, 0.3 mm, 0.4 mm, 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, or0.9 mm; and/or less than or equal to 1.0 mm, 0.9 mm, 0.8 mm, 0.7 mm, 0.6mm, 0.5 mm, 0.4 mm, 0.3 mm, 0.2 mm, or 0.1 mm.

The perforations can have an average center-to-center pitch of from 0.1mm to 50 mm. For example, the average center-to-center pitch can begreater than or equal to 0.2 mm, 0.3 mm, 0.4 mm, 0.5 mm, 0.6 mm, 0.7 mm,0.8 mm, 0.9 mm, 1.0 mm, 1.25 mm, or 1.5 mm; and/or less than or equal to1.5 mm, 1.25 mm, 1.0 mm, 0.9 mm, 0.8 mm, 0.7 mm, 0.6 mm, 0.5 mm, 0.4 mm,0.3 mm, or 0.2 mm.

The perforations can be quadrangular in shape, for instance, square andrectangles. The perforations can have an average hole length to holewidth ratio of from 0.1:1 to 1000:1. For example, the average length towidth ratio can be greater than or equal to 0.1:1, 1:1, 2:1, 3:1, 4:1,5:1, 6:1, 7:1, 8:1, 9:1, 10:1, 15:1, 20:1, 25:1, 50:1, 100:1, 150:1,200:1, 250:1, 300:1, 350:1, 450:1, 500:1, 550:1, 600:1, 650:1, 700:1,750:1, 800:1, 850:1, 900:1, 950:1, and/or less than or equal to 1000:1,950:1, 900:1, 850:1, 800:1, 750:1, 700:1, 650:1, 600:1, 550:1, 500:1,450:1, 400:1, 350:1, 300:1, 250:1, 200:1, 150:1, 100:1, 50:1, 25:1,20:1, 15:1, 10:1, 9:1, 8:1, 7:1, 6:1, 5:1, 4:1, 3:1, 2:1, or 1:1.

In some embodiments, the holes can be triangular. Generally, thetriangular holes will be equilateral triangles, with sides that are from0.01 mm to 1 mm in length. For example, the average triangle side lengthcan be greater than or equal to 0.05 mm, 0.1 mm, 0.2 mm, 0.3 mm, 0.4 mm,0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, or 0.9 mm; and/or less than or equal to1.0 mm, 0.9 mm, 0.8 mm, 0.7 mm, 0.6 mm, 0.5 mm, 0.4 mm, 0.3 mm, 0.2 mm,or 0.1 mm.

In some embodiments, the holes can be substantially circular. Circularholes can have a diameter from about 0.05 to 1.0 mm. For example, theaverage hole diameter can be greater than or equal to 0.05 mm, 0.1 mm,0.2 mm, 0.3 mm, 0.4 mm, 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, or 0.9 mm;and/or less than or equal to 1.0 mm, 0.9 mm, 0.8 mm, 0.7 mm, 0.6 mm, 0.5mm, 0.4 mm, 0.3 mm, 0.2 mm, or 0.1 mm.

In some embodiments, the porous membrane can be dimpled. Dimples can besimilar to perforations in the manner they are disposed on the porousmembrane, however, dimples are indentations, rather than complete voids,in the surface of the porous membrane. The thickness of the dimples canbe from 1-99% the thickness of the porous membrane. For examples, theaverage thickness of the dimples can be less than 95%, 90%, 85%, 80%,75%, 70%, 65%, 60%, 55%, 50%, 45%, 40%, 35%, 30%, 25%, 20%, 15%, 10%, or5% that of the porous membrane. Dimples may be arranged in rows alongthe porous membrane. The rows or lines may be spaced 0.001 mm to 10 mmapart. For example, the rows can be 0.05 mm, 0.1 mm, 0.2 mm, 0.3 mm, 0.4mm, 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm, 1.0 mm, 1.2 mm, 1.4 mm, 1.6mm, 1.8 mm, 2.0 mm, 2.25 mm, 2.5 mm, 2.75 mm, 3 mm, 4 mm, 5 mm, 6 mm, 7mm, 8 mm, 9 mm, or 10 mm apart.

The dimples may have an average dimple length of from 0.05 mm to 1 mm.For example, the average dimple length can be greater than or equal to0.05 mm, 0.1 mm, 0.2 mm, 0.3 mm, 0.4 mm, 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm,or 0.9 mm; and/or less than or equal to 1.0 mm, 0.9 mm, 0.8 mm, 0.7 mm,0.6 mm, 0.5 mm, 0.4 mm, 0.3 mm, 0.2 mm, or 0.1 mm.

The dimples may have an average dimple width of from 0.01 mm to 1 mm.For example, the average dimple width can be greater than or equal to0.05 mm, 0.1 mm, 0.2 mm, 0.3 mm, 0.4 mm, 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm,or 0.9 mm; and/or less than or equal to 1.0 mm, 0.9 mm, 0.8 mm, 0.7 mm,0.6 mm, 0.5 mm, 0.4 mm, 0.3 mm, 0.2 mm, or 0.1 mm.

The dimples can have an average center-to-center pitch of from 0.1 mm to50 mm. For example, the average center-to-center pitch can be greaterthan or equal to 0.2 mm, 0.3 mm, 0.4 mm, 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm,0.9 mm, 1.0 mm, 1.25 mm, or 1.5 mm; and/or less than or equal to 1.5 mm,1.25 mm, 1.0 mm, 0.9 mm, 0.8 mm, 0.7 mm, 0.6 mm, 0.5 mm, 0.4 mm, 0.3 mm,or 0.2 mm.

The dimples can be quadrangular in shape, for instance, square andrectangles. The dimples can have an average dimple length to dimplewidth ratio of from 0.1:1 to 100:1. For example, the average length tobase width ratio can be greater than or equal to 0.1:1, 1:1, 2:1, 3:1,4:1, 5:1, 6:1, 7:1, 8:1, 9:1, 10:1, 15:1, 20:1, 25:1, 50:1, 100:1,150:1, 200:1, 250:1, 300:1, 350:1, 450:1, 500:1, 550:1, 600:1, 650:1,700:1, 750:1, 800:1, 850:1, 900:1, 950:1, and/or less than or equal to1000:1, 950:1, 900:1, 850:1, 800:1, 750:1, 700:1, 650:1, 600:1, 550:1,500:1, 450:1, 400:1, 350:1, 300:1, 250:1, 200:1, 150:1, 100:1, 50:1,25:1, 20:1, 15:1, 10:1, 9:1, 8:1, 7:1, 6:1, 5:1, 4:1, 3:1, 2:1, or 1:1.

In some embodiments, the dimples can be substantially circular. Circulardimples can have a diameter from about 0.05 to 1.0 mm. For example, theaverage dimple diameter can be greater than or equal to 0.05 mm, 0.1 mm,0.2 mm, 0.3 mm, 0.4 mm, 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, or 0.9 mm;and/or less than or equal to 1.0 mm, 0.9 mm, 0.8 mm, 0.7 mm, 0.6 mm, 0.5mm, 0.4 mm, 0.3 mm, 0.2 mm, or 0.1 mm.

In some embodiments, the porous membrane can feature a combination ofserrations, holes, slits, and/or dimples. For instance, a porousmembrane can have a series of serrated ribs running top to bottom alongthe separator, and a second series of serrated ribs running horizontallyalong the separator. In other embodiments, the porous membrane can havean alternating sequence of serrated ribs, dimples and/or perforations.Also, a pocket, sleeve or wrap separator may have openings or slits toallow acid movement.

In accordance with at least one embodiment, the porous membrane is madeup of an ultrahigh molecular weight polyethylene (UHMWPE) mixed with aprocessing oil plus additive and precipitated silica. In accordance withat least one other embodiment, the porous membrane is made up of anultrahigh molecular weight polyethylene (UHMWPE) mixed with a processingoil and precipitated silica. The processing oil can be optionallyremoved as described above. The additive can then be applied to theporous membrane via one or more of the techniques described above. Inaccordance with at least one particular embodiment, the negative crossribs are rounded mini-ribs and preferably have a 2 to 6 mil radius and a10 to 50 mil rib spacing.

In accordance with at least selected embodiments, the porous membraneincludes a porous membrane having a backweb and optionally having one ormore positive ribs and/or negative ribs thereon. For example, the porousmembrane may include a porous membrane having a backweb and at least twopositive ribs on the positive side of the backweb, and optionally aplurality of smaller negative cross ribs or transverse ribs on thenegative side of the backweb. The positive ribs may be straight or wavy,may have a solid portion, may have a truncated pyramidal shape, may beserrated, battlemented, discontinuous, continuous, nubs, protrusions, orcombinations thereof. The negative ribs may be smaller than the positiveribs and may be straight or wavy, may have a solid portion, may have atruncated pyramidal shape, may be serrated, battlemented, discontinuous,continuous, nubs, protrusions, mini-ribs, transverse, longitudinal, orcombinations thereof. Also, the positive and negative face ribs may bethe same size (the same size on both sides) and may be parallel, angledor perpendicular to each other. For example, both sides may have smallor mini ribs and such ribs may be parallel, angled or perpendicular toeach other. The membrane may be selected from the group of polyolefin,rubber, polyvinyl chloride, phenolic, cellulosic, or combinationsthereof, and the membrane is preferably a polyolefin (PO) material, morepreferably polyethylene (PE), forming a porous or microporous membranefor a battery separator for a storage battery.

In at least one embodiment, the porous membrane is made of amicroporous, thermoplastic material which is provided with longitudinalpositive ribs and transverse negative ribs with the height of at least amajority of the longitudinal ribs being greater than that of thetransverse ribs, and the longitudinal and transverse ribs being solidribs which are formed integrally from the plastic, characterized in thatthe transverse ribs extend across substantially the entire back width ofthe separator. The porous membrane back web or sheet thickness may beapproximately 0.10 to 0.50 mm, the height of the longitudinal ribs maybe 0.3 to 2.0 mm and the height of the transverse ribs may be 0.1 to 0.7mm, the longitudinal rigidity with 100 mm width may be approximately 5mJ and the transverse rigidity may be approximately 2.5 mJ, and thetotal thickness of the porous membrane may be less than 3.5 mm,preferably less than 2.5 mm.

Coating Materials

The exemplary coating materials described herein can impart, forexample, improved oxidation resistance, improved wettability, reducedblack residue, improved surface conductivity, increased stiffness,and/or improved resistance to metal contamination induced oxidiation inthe above-described porous membranes. The coating materials can increasecharge acceptance and/or reduce acid stratification in batteries,especially lead acid batteries. In some embodiments, the coatingmaterial is hydrophilic, porous, conductive, oxidation resistant, orself-adhering to a porous membrane. In some selected embodiments, thecoating material is hydrophilic and porous, or hydrophilic, porous, andoxidation resistance, or hydrophilic, porous, and conductive, orhydrophilic, porous, oxidation resistant and conductive, or anycombination thereof.

Exemplary coating materials include, but are not limited to, silica,fumed silica, silicon oxides, alumina, aluminum oxides, metals, metaloxides, cellulose, carbon, and conductive carbon materials. In certainembodiments, the coating material is a single type of material, while inother embodiments, the coating material contains two or more of theabove mentioned materials, for instance, silica and silicon oxides,alumina and aluminum oxide, silica and carbon, etc.

Exemplary metal oxides that may be present in the coating layer includealuminum oxide (Al₂O₃), boehmite γ-AlO(OH), silicon oxide, and oxides oftransition metals and the like or mixtures thereof.

Exemplary conductive carbons include graphite, graphene, grapheneoxides, carbon nanotubes, carbon fibers, or the like.

In certain selected embodiment, the coating layer may contain one of theforegoing materials in combination with a polymer, binder or carriermaterial. Exemplary carrier materials include glass mats, ceramics, andpolymers. Exemplary polymers include polyolefins, PVDF, PVDF:HFP, PEO,PTFE, SBR, PVA, acrylic, and/or the like. In certain embodiments, thecarrier mixture is blended homogenously with the foregoing materials,and in other embodiments, the materials are present as an agglomerationof particles.

The coating layer may be present on the face of the porous membranefacing the positive electrode, the face of the porous membrane facingthe negative electrode, or both faces of the porous membrane. In certainembodiments, the face of the porous membrane that faces the positiveelectrode may be coated with one material, while the face of the porousmembrane that faces the negative electrode may be coated with adifferent material. In other embodiments, both faces are coated orover-coated with the same material.

The coating layer or layers may be present on either side of the porousmembrane, at a thickness of the range of 0.1 μm to 250 μm, possiblypreferably of 1 to 250 μm, 1 to 150 μm, 2.5 to 150 μm, 2.5 to 125 μm,2.5 to 100 μm, 2.5 to 75 μm, 5 to 75 μm, 5 to 100 μm, 10 to 100 μm, 5 to50 μm, 5 to 25 μm, 25 to 100 μm, 25 to 50 μm, or 25 to 75 μm. In otherembodiments, the coating may be applied at very thin thickness, forinstance, less than 5 μm, 4 μm, 3 μm, 2 μm, 1 μm, 0.5 μm, or 0.25 μm. Inother embodiments, the coating may be applied at thicker rate, forinstance, more than 5 μm, 10 μm, 15 μm, 20 μm, 25 μm, 30 μm, 35 μm, 40μm, 50 μm, 75 μm, 100 μm or 150 μm.

Coated Porous Membranes

The coated porous membranes described herein are preferablycharacterized by enhanced stiffness, oxidation resistance, wettability,and/or surface conductivity, resistance to contamination inducedoxidation, reduced black residue, and/or the like.

Methods of Coating Porous Separators

In certain embodiments, the coating layer covers the entirety of theporous membrane, while in other embodiments, the coating covers aportion of the porous membrane, for instance, on the ribs, on thebackweb, on the positive face, on the negative face, and/or in stripes,ribbons, other patterns, and/or the like. The substrate or membrane canbe a flat PE membrane, a ribbed PE membrane, an AGM, or other substrate.When the coating layer is applied as ribs or stripes or other patterns,the preferred substrate or membrane may be substantially flat. Thecoating layer may be applied to a porous membrane (or to just the ribs)via a dip, knife, curtain, gravure, solvent coating, aqueous coating,physical vapor deposition method, an atomic layer deposition method, ora chemical vapor deposition method. Physical vapor deposition (PVD) mayinclude a variety of vapor and/or vacuum deposition methods used todeposit thin films by the condensation of a vaporized form of thedesired film material onto various substrate surfaces. PVD is used inthe manufacture of various items, including, by way of example only,semiconductor devices, aluminized PET film for balloons and foodpackaging bags, and coated cutting tools for metalworking. Vacuummetallizing is a form of physical vapor deposition, a process ofcombining metal with a non-metallic substrate through evaporation. Themost common metal used in vacuum metallization is aluminum for a varietyof reasons such as cost, thermodynamics, and reflective properties.

In certain embodiments there are provided a very thin coating on aporous membrane. Such embodiments may be desirable because it occupiesless volume in a battery and may enable a battery to have highervolumetric and gravimetric energy density.

In forming the coating layers described herein, a vapor depositiontechnology may be employed to deposit a very thin layer of a coatinglayer at an ultra-thin thickness of less than 1 μm. Physical vapordeposition (PVD), chemical vapor deposition (CVD) and atomic layerdeposition (ALD) are three commonly known types of vapor depositiontechnology. Non-limiting examples of physical vapor deposition aresputter and evaporation. Physical vapor deposition may involvevaporizing a metallic element, a reactive metallic element, an inertmetallic element, or a metal oxide and forming a layer on a substratesuch as a porous membrane. A vapor deposition layer may be depositedonto a porous membrane, which vapor deposition layer is comprised of asingle layer of individual atoms or molecules of highly oxidationresistant materials such as a metal and/or metal oxide. Furthermore, avapor deposition layer may be deposited onto a porous membrane, whichvapor deposition layer is comprised of multiple layers of individualatoms or molecules of highly oxidation resistant materials such as aninert metallic element, a reactive metallic element, or a metal oxidecompound. In addition, one or more layers of possible combinationsapplied in various orders of a metal and/or metal oxide may be formed ata thickness of less than one μm, more preferably at a thickness of lessthan approximately 0.5 μm, more preferably less than approximately 1,000Å, and most preferably at a thickness less than approximately 500 Å on amicroporous membrane.

Atomic layer deposition (ALD) which is a film growth method thatdeposits a deposition in layers, may also be used to apply a coatinglayer in a controlled fashion. In general, a vapor of film precursor isabsorbed on a substrate in a vacuum chamber. The vapor is then pumpedfrom the chamber, leaving a thin layer of absorbed precursor, usuallyessentially a monolayer, on the substrate. A reactant is then introducedinto the chamber under thermal conditions, which promote reaction withthe absorbed precursor to form a layer of the desired material. Thereaction products are pumped from the chamber. Subsequent layers ofmaterial can be formed by again exposing the substrate to the precursorvapor and repeating the deposition process. ALD can produce very thinfilms of nanometer range with extremely dense layer production and aminimum amount of defects.

Chemical vapor deposition (CVD) technology may also be used to apply acoating layer in a controlled fashion. Chemical vapor deposition isanother widely used materials-processing technology to apply solidthin-films to surfaces. It has been used to deposit a very wide range ofmaterials. In its simplest incarnation, CVD involves flowing a precursorgas or gases into a chamber containing one or more heated objects ontowhich the CVD layer is to be applied. Chemical reactions occur on andnear the hot surfaces, resulting in the deposition of a thin film on thesurface. This is accompanied by the production of chemical by-productsthat are exhausted out of the chamber along with unreacted precursorgases. It can be done in hot-wall reactors and cold-wall reactors, atsub-torr total pressures to above-atmospheric pressures, with andwithout carrier gases, and at temperatures typically ranging from200-1600° C. There are also a variety of enhanced CVD processes, whichinvolve the use of plasmas, ions, photons, lasers, hot filaments, orcombustion reactions to increase deposition rates and/or lowerdeposition temperatures.

Application of a deposition layer or layers using PVD, CVD or ALD mayprovide reliable methods to control the added thickness of a depositionof coating material. In certain selected embodiments, the thickness ofthe deposition layer or layers may be ultra-thin and in the range ofless than approximately 5 μm, more preferably less than approximately 1μm, more preferably less than approximately 1,000 Å, and most preferablyat a thickness less than approximately 500 Å. Such a reliable method ofapplying an ultra-thin deposition at a thickness less than 1 μm may notbe attained using, for example, other coating methods such as dip,gravure, knife, curtain, etc. coating methods. An application of anultra-thin deposition using one or more of the PVD, CVD or ALDdeposition methods may provide a reliable method to apply a uniformoxidation resistant layer. The level of application control achieved inPVD, CVD or ALD deposition methods may have sufficient accuracy so as tocontribute an insignificant increase in thickness of a polymericmicroporous membrane.

Such layers or coatings may be applied as a coating slurry or mixture ora layer onto one or both sides of a microporous battery separatormembrane in order to, among other things, promote high temperaturestability, reduce acid stratification, improve wettability, improvestiffness, reduce thermal shrinkage, control oxidation at theseparator-positive electrode interface of the battery, and improvesafety performance of the microporous battery separator membrane in abattery. Such coatings may be applied using known technologies such as,but not limited to, dip coating, knife, gravure, curtain, etc. and canbe applied at a thickness of approximately 2 μm to 6 μm, 5 μm to 75 μm,and the like, or more, onto one or both sides of a microporous batteryseparator membrane.

In accordance with certain embodiments, polymeric and/or ceramicparticle-containing polymeric coatings may be applied on top of or inaddition to a metal and/or metal oxide deposition layer in order tofurther improve various properties of the separator, for example, thethermal stability of the separator membrane at high temperatures.

In accordance with certain embodiments, the battery separator membranedescribed herein is directed to a polymeric microporous membrane towhich is applied a deposition layer comprising a highly oxidationresistant material such as an inert metallic element where thedeposition layer thickness is in the range of approximately 20 Å toapproximately 1 μm. Non-limiting examples of an inert metallic elementmay be gold and platinum. A deposition of a chemically stable metal suchas gold or platinum onto a microporous polymeric membrane or film maycreate an oxidation resistant layer when the side of the microporouspolymeric membrane bearing the deposition layer is placed in contactwith the cathode. When a battery is a high voltage battery oxidation maybe more aggressive, and a protective oxidation resistant layer isdesirable to limit the oxidative degradation of the microporouspolymeric membrane against the cathode. A metal deposition layeraccording to various embodiments herein is a conductive layer and maydissipate current distribution within a battery cell. In at leastcertain embodiments, the inventive metal conductive deposition layerdescribed herein may be applied to a non-conductive layer or layers of apolymer, such as a polyolefin, such as, but not limited to, apolypropylene, a polypropylene blend, a polypropylene copolymer, ormixtures thereof and a polyethylene, a polyethylene blend, apolyethylene copolymer, or mixtures thereof. Non-limiting examples ofthe non-conductive layer may include single layer, bilayer, trilayer ormultilayer (coextruded or laminated) porous membranes manufactured by adry process or by a wet process, with added glass mats or other woven ornonwoven layers, which are commonly known by those skilled in the art.

In accordance with at least certain embodiments, examples of a reactivemetal element may include aluminum (Al), which is a conductive metal. Asan example of a reactive metal element, when exposed to oxygen in air,aluminum will form an ultra-thin protective layer of aluminum oxide(Al₂O₃). A layer of Al₂O₃ may be stable against further oxidation inair.

Various non-limiting examples may offer different property sets orimprovements that may include one or any combination of the following:

-   -   1. One exemplary embodiment of a conductivity enhancement may        provide carbon, which may be deposited by a variety of methods        as described herein, or otherwise known in the art, on one or        both sides of the separator.    -   2. Another exemplary embodiment may provide oxidation resistance        by depositing alumina, silica, etc. by various methods as        described herein or otherwise known in the art, on the positive        side of the separator.    -   3. Yet another exemplary embodiment may provide black residue        reduction by the use of less oil on one or both sides of the        separator.    -   4. Still another exemplary embodiment may provide stiffness to        the separator by depositing alumina, silica, etc. by various        methods as described herein or otherwise known in the art, on        one or both sides of the separator.    -   5. Another exemplary embodiment may address acid stratification        by incorporating silica, fibers, glass fibers, cellulosic fibers        etc. deposited by various methods and with a combination of        materials as described herein on the positive side of the        separator.    -   6. Another exemplary embodiment may include incorporating        cellulosic coating which will provide resistance to oxidation        induced by metal contaminants such as Cr, Mn, etc.    -   7. Further, another exemplary embodiment may incorporate a        variety of geometries, such as by replacing rib alone by        coating, cover glass fibers as coating, glass fibers, cellulosic        fibers or mixture of fiber and silica, etc.    -   8. Still further, the exemplary embodiments provided in any one        of FIGS. 2-4.    -   9. Yet further, the exemplary embodiments provided in any one of        FIGS. 5A and 5B.    -   10. Still yet further, the exemplary embodiments provided in        FIGS. 7 and 7A.    -   11. Another embodiment may include fumed silica mixed with        binder on positive side by roller coating, carbon on negative        side by PVD.    -   12. Another embodiment may include film of Cellulose with        phenol-formaldehyde binder on positive side, carbon on negative        side.

The range of stiffness of the separator may be measured by theresistance to bending, such as by an industry standard test or asspecified in BSTE:2530. Oxidation stability may be measured by: 1)weight loss incurred in hot sulfuric acid containing peroxodisulfate(hydrogen peroxide); or 2) the Perox-80 test; or 3) by an industrystandard test or as specified in BSTE-2100, 2100-3, and BSTE-2520. Therange of wettability is measured in minutes (usually 3 minutes and 10minutes) and can be measured by immersing the separator horizontally andmeasure the wettability with respect to time, such as by an industrystandard test or as specified in BSTE:2540, and 2543. The range ofsurface conductivity may be measured by electrochemical impedancespectroscopy.

In accordance with at least selected embodiments, the presentapplication or invention is directed to novel or improved porousmembranes or substrates, separator membranes, separators, composites,electrochemical devices, batteries, methods of making such membranes orsubstrates, separators, and/or batteries, and/or methods of using suchmembranes or substrates, separators and/or batteries. In accordance withat least certain embodiments, the present application is directed tonovel or improved microporous membranes, battery separator membranes,separators, energy storage devices, batteries including such separators,methods of making such membranes, separators, and/or batteries, and/ormethods of using such membranes, separators and/or batteries. Inaccordance with at least certain selected embodiments, the presentinvention is directed to a separator for a battery which has anoxidation protective deposition layer or layers. The deposition layer ispreferably a thin or ultra-thin deposition of conductive or insulatinglayers applied to a polymeric microporous membrane. Methods could use abinder that goes away upon post treatment or a solvent such as waterthat gets removed during post-process such as heating/curing/annealing,etc. Also, methods could use a binder that does not go away (the bindermay remain or stay back) and holds the fibers or particles together inwet coatings. Another method includes a binder-free and solvent-freedeposition method. By employing a deposition layer, the energy densityof a battery may be increased. Furthermore, the deposition method maypreferably deposit a uniform layer that is less than about 0.5 μm. Inaccordance with at least particular embodiments, the battery separatormembrane described herein is directed to a multilayer or compositemicroporous membrane battery separator which may have excellentoxidation resistance and may be stable in a high voltage battery systemup to. In accordance with at least other selected embodiments, thepresent invention is directed to a separator for a battery which has aconductive deposition layer which is stable in electrolyte and in thebattery operating conditions.

The present invention may be embodied in other forms without departingfrom the spirit and the essential attributes thereof, and, accordingly,reference should be made to the appended claims, rather than to theforegoing specification, as indicating the scope of the invention.Additionally, the invention illustratively disclosed herein suitably maybe practiced in the absence of any element which is not specificallydisclosed herein.

Improved battery separators are disclosed herein for use in various leadacid batteries. The improved separators disclosed herein provide leadacid batteries having substantially increased battery life, improvedcharge acceptance, improved oxidation resistance, improved surfaceconductivity, improved stiffness, improved wettability, andsubstantially reduced battery fail rate and acid stratification.

In accordance with at least selected embodiments, aspects or objects,the present application or invention is directed to novel or improvedporous membranes or substrates, separator membranes, separators,composites, electrochemical devices, batteries, methods of making suchmembranes or substrates, separators, and/or batteries, and/or methods ofusing such membranes or substrates, separators and/or batteries. Inaccordance with at least certain embodiments, the present application isdirected to novel or improved porous membranes having a coating layer,battery separator membranes having a coating layer, separators, energystorage devices, batteries, including lead acid batteries including suchseparators, methods of making such membranes, separators, and/orbatteries, and/or methods of using such membranes, separators and/orbatteries. The disclosed separators and batteries may have improvedcharge acceptance, improved surface conductivity, improved oxidationresistance, reduced acid stratification, reduced black residue, improvedwettability, and/or improved stiffness.

In accordance with at least selected embodiments, the presentapplication or invention is directed to novel or improved porousmembranes or substrates, separator membranes, separators, composites,electrochemical devices, batteries, methods of making such membranes orsubstrates, separators, and/or batteries, and/or methods of using suchmembranes or substrates, separators and/or batteries. In accordance withat least certain embodiments, the present application is directed tonovel or improved porous membranes having a coating layer, batteryseparator membranes having a coating layer, separators, energy storagedevices, batteries, including lead acid batteries including suchseparators, methods of making such membranes, separators, and/orbatteries, and/or methods of using such membranes, separators and/orbatteries. The disclosed separators and batteries have improved chargeacceptance, improved surface conductivity, improved oxidationresistance, reduced acid stratification, improved resistance to metalcontamination induced oxidation, reduced black residue, improvedwettability, and/or improved stiffness.

In accordance with at least certain selected embodiments, the presentinvention is directed to a separator for a battery that is a microporouspolymer membrane functionalized, coated, treated, or the like to add atleast one material, treatment, function, or layer on at least one sidethereof. In certain selected particular embodiments, the material,treatment, function, or layer may or may not include a binder, mayinclude one or more materials such as silica, silicon oxides, alumina,aluminum oxides, metals, metal oxides, conductive carbon materials, acidstabilized cellulose, and/or the like, and/or may include one or moreconductive or dielectric or insulating layers.

In accordance with at least certain embodiments, a method of obtainingimproved separators is provided in which a treatment, material or layeris applied to at least one surface or side of a polymeric microporousmembrane, a polyethylene (PE) microporous membrane, a woven or nonwovenmaterial, a nonwoven glass mat, a nonwoven absorptive glass mat (AGM), anonwoven or woven PET, cellulose nonwoven mat, and/or the like. Thematerial, treatment or layer can be applied by vapor deposition,chemical deposition, vacuum assisted methods, PVD, CVD, TD, DCD, PACVD,DLC, thin-film coating or deposition technology, nano-film technology,single atom thick coating technology, sol-gel, solvent coating, aqueouscoating, and/or the like. In some embodiments the material, treatment,coating, layer, or function is applied or added by a solvent-freemethod, a binder-free method, or a solvent and binder free method. Inother selected embodiments, the layer is applied in the presence of abinder and/or solvent which may be subsequently removed post-process.

In accordance with at least selected embodiments, a porous membrane witha porous or ionically conductive coating or layer is provided as abattery separator in a lead acid battery and may improve the cycle life,cranking ability and high charge acceptance of the battery.

In accordance with at least particular embodiments, the batteryseparators described herein are directed to a multilayer or compositemicroporous membrane battery separator which may have excellentoxidation resistance and are stable in a lead acid battery system. Inaccordance with at least other selected embodiments, the presentinvention is directed to a battery separator having a layer whichincreases oxidation resistance, improved oxidation resistance in thepresence of metal ion contamination such as chromium ions, reduces acidstratification, improves surface conductivity, improves chargeacceptance, increases stiffness, runnability and processability, and/orincreases surface wettability.

In accordance with at least selected embodiments, the presentapplication or invention is directed to novel, improved or optimizedporous films, membranes or substrates, functionalized, coated or treatedporous films, membranes or substrates, novel, improved, optimized,functionalized, coated, or treated separator membranes, separators,multilayer separators, lead acid battery separators, or composites,electrochemical devices, batteries, or cells including such films,membranes, substrates, separator membranes, separators, lead acidbattery separators, or composites, novel, improved or optimizedcombinations or systems of plates or electrodes with such films,membranes, substrates, separator membranes, separators, lead acidbattery separators, or composites, methods of making such films,membranes, substrates, separator membranes, separators, lead acidbattery separators, composites, systems, combinations, cells, devices,and/or batteries, and/or methods of using such films, membranes,substrates, separator membranes, separators, lead acid batteryseparators, composites, systems, combinations, cells, devices, and/orbatteries. In accordance with at least certain embodiments, the presentapplication is directed to novel, improved, or optimized,functionalized, coated, or treated microporous membranes, batteryseparator membranes, lead acid battery separator membranes, separators,and/or lead acid battery separators having at least one functionalized,coated, or treated surface on at least one side thereof, having at leastone coating, film, layer, or material on at least one side, rib orsurface thereof, energy storage devices, cells, systems, combinations,and/or batteries including such membranes, battery separator membranes,lead acid battery separator membranes, separators, and/or lead acidbattery separators, methods of making such membranes, battery separatormembranes, lead acid battery separator membranes, separators, and/orlead acid battery separators, and/or methods of using such membranes,battery separator membranes, lead acid battery separator membranes,separators, lead acid battery separators, composites, combinations,systems, devices, cells, and/or batteries, and/or the like.

The foregoing written description of structures, devices and methodshave been presented for purposes of illustration only. Examples are usedto disclose exemplary embodiments, including the best mode, and also toenable any person skilled in the art to practice the invention,including making and using any devices or systems and performing anyincorporated methods. These examples are not intended to be exhaustiveor to limit the invention to the precise steps and/or forms disclosed,and many modifications and variations are possible in light of the aboveteaching. Features described herein may be combined in any combination.Steps of a method described herein may be performed in any sequence thatis physically possible. The patentable scope of the invention is definedby the appended claims, and may include other examples that occur tothose skilled in the art. Such other examples are intended to be withinthe scope of the claims if they have structural elements that do notdiffer from the literal language of the claims, or if they includeequivalent structural elements with insubstantial differences from theliteral language of the claims.

The compositions and methods of the appended claims are not limited inscope by the specific compositions and methods described herein, whichare intended as illustrations of a few aspects of the claims. Anycompositions and methods that are functionally equivalent are intendedto fall within the scope of the claims. Various modifications of thecompositions and methods in addition to those shown and described hereinare intended to fall within the scope of the appended claims. Further,while only certain representative compositions and method stepsdisclosed herein are specifically described, other combinations of thecompositions and method steps also are intended to fall within the scopeof the appended claims, even if not specifically recited. Thus, acombination of steps, elements, components, or constituents may beexplicitly mentioned herein or less, however, other combinations ofsteps, elements, components, and constituents are included, even thoughnot explicitly stated.

As used in the specification and the appended claims, the singular forms“a,” “an,” and “the” include plural referents unless the context clearlydictates otherwise. Ranges may be expressed herein as from “about” oneparticular value, and/or to “about” another particular value. When sucha range is expressed, another embodiment includes from the oneparticular value and/or to the other particular value. Similarly, whenvalues are expressed as approximations, by use of the antecedent“about,” it will be understood that the particular value forms anotherembodiment. It will be further understood that the endpoints of each ofthe ranges are significant both in relation to the other endpoint, andindependently of the other endpoint.

“Optional” or “optionally” means that the subsequently described eventor circumstance may or may not occur, and that the description includesinstances where said event or circumstance occurs and instances where itdoes not.

Throughout the description and claims of this specification, the word“comprise” and variations of the word, such as “comprising” and“comprises,” means “including but not limited to,” and is not intendedto exclude, for example, other additives, components, integers, orsteps. The terms “consisting essentially of” and “consisting of” can beused in place of “comprising” and “including” to provide for morespecific embodiments of the invention and are also disclosed.“Exemplary” means “an example of” and is not intended to convey anindication of a preferred or ideal embodiment. “Such as” is not used ina restrictive sense, but for explanatory or exemplary purposes.

Other than where noted, all numbers expressing geometries, dimensions,and so forth used in the specification and claims are to be understoodat the very least, and not as an attempt to limit the application of thedoctrine of equivalents to the scope of the claims, to be construed inlight of the number of significant digits and ordinary roundingapproaches.

Unless defined otherwise, all technical and scientific terms used hereinhave the same meanings as commonly understood by one of skill in the artto which the disclosed invention belongs. Publications cited herein andthe materials for which they are cited are specifically incorporated byreference.

What is claimed is:
 1. A lead acid battery separator comprising: aporous membrane or substrate having at least one electricallynon-conductive, conductive or semiconductive layer, film, coating,deposition, or material; the porous membrane or substrate having aresidual processing oil in an amount no more than 20% by weight; thelayer, film, coating, deposition, or material has a thickness of therange of 5 μm to 125 μm; the layer, film, coating, deposition, ormaterial comprising a conductive carbon, a metal oxide, and at least oneof particles, fibers or materials of at least one of silica, fumedsilica, silicon oxide, alumina, metal, cellulose, cellulosic material,glass, fiber glass, carbon, or combinations, blends or mixtures thereofon at least one side thereof.
 2. The lead acid battery separatoraccording to claim 1, wherein the conductive carbon is selected fromgraphite, graphene, carbon nanotubes, graphene oxides, carbon fibers,and combinations, blends or mixtures thereof.
 3. The lead acid batteryseparator according to claim 1, wherein the metal oxide is selected fromaluminum oxide (Al₂O₃), boehmite (AlO(OH)), silicon oxide, fumed silica,oxides of transition metals, and combinations, blends or mixturesthereof.
 4. The lead acid battery separator according to claim 1,further comprising a silica, silicon oxide, alumina, or combinations,blends or mixtures thereof.
 5. The lead acid battery separator accordingto claim 1, wherein the layer further comprises a polymer, binder orcarrier material.
 6. The lead acid battery separator according to claim5, wherein the carrier or binder comprises one or more glass mats, fibermats, synthetic mats, ceramics, and polymers.
 7. The lead acid batteryseparator according to claim 5, wherein the polymer comprises one ormore polymers, inorganic or organic polymers or polymeric materials,polymeric binders, organic binder, acrylic resin, cellulose, polyolefin,PVDF, PVDF:HFP, PEO, PTFE, SBR, PVA, phenol formaldehyde resin, oracrylate.
 8. The lead acid battery separator according to claim 1,wherein the porous membrane comprises one or more thermoplasticpolymers.
 9. The lead acid battery separator according to claim 8,wherein the thermoplastic polymer comprises polyethylene.
 10. The leadacid battery separator according to claim 1, wherein the porous membraneor substrate comprises ribs, serrations, embossing, corrugation,perforations, or dimples.
 11. The lead acid battery separator accordingto claim 1, wherein the porous membrane or substrate comprises PE, PO,PVC, cellulose, rubber, glass mat, fiber mat, synthetic mat, or AGM. 12.The lead acid battery separator according to claim 1, wherein the porousmembrane or substrate comprises one or more additives or agents.
 13. Thelead acid battery separator according to claim 1, wherein the porousmembrane comprises processing oil in an amount no more than 18% byweight.
 14. A lead acid battery comprising the separator according toclaim
 1. 15. A method of making the battery separator according to claim1, comprising the step of: applying at least one electricallynon-conductive, conductive or semiconductive layer, film, coating,deposition, or material comprising conductive carbon and at least one ofparticles, fibers or materials of at least one of silica, fumed silica,silicon oxide, alumina, metal, metal oxide, cellulose, cellulosicmaterial, glass, fiber glass, carbon, or combinations, blends ormixtures thereof on at least one side of a porous or microporousmembrane or substrate; the porous membrane or substrate having aresidual processing oil in an amount no more than 20% by weight.
 16. Themethod according to claim 15, wherein the layer is applied via a dip,knife, curtain, gravure, solvent coating, aqueous coating, organiccoating, physical vapor deposition method, an atomic layer depositionmethod, or a chemical vapor deposition method.
 17. The method accordingto claim 15, wherein a different layer is applied to each side of theporous membrane or substrate.
 18. The method according to claim 15,wherein two layers are applied to one side of the porous membrane orsubstrate.